Embarking on your composting journey? You’ve come to the right place! Composting is an incredibly rewarding practice that transforms organic waste into nutrient-rich soil amendment, often called “black gold.” Not only does it enrich your garden soil, fostering healthier plants and robust harvests, but it also significantly reduces the amount of household waste sent to landfills, contributing to a more sustainable planet. For beginners and seasoned gardeners alike, understanding precisely what can – and cannot – go into your compost pile is key to success.
Many aspiring composters feel a bit overwhelmed when they first start, unsure of which kitchen scraps and yard waste are safe to add, and which might cause problems like attracting pests or introducing harmful pathogens. While a wide variety of organic materials are compostable, some require special consideration, and others should be avoided entirely to maintain a healthy, active compost system. Our comprehensive guide is designed to clarify these common confusions, providing you with a definitive list of over 100 items to help you compost confidently and effectively.
Creating your own composting bin can be a simple and cost-effective endeavor. If you’re looking for inspiration, explore these 35 cheap and easy DIY composting bin ideas that you can build in a weekend. Whether you’re aiming for a small kitchen counter compost or a large backyard system, having the right knowledge about what goes into it is fundamental.
This ultimate guide will break down the dos and don’ts of composting, ensuring your compost pile thrives and produces the best possible amendments for your garden. Let’s dive into what you need to know to become a composting pro!
Understanding What Not to Compost: Essential Items to Avoid
1. Coal and Charcoal Ash
While wood ash is often a welcome addition to a compost pile in moderation, coal and charcoal ashes are strictly off-limits. The key difference lies in their composition. Coal and charcoal, especially briquettes, often contain a range of harmful chemicals, heavy metals, and sulfur that can leach into your compost. These toxins can contaminate your finished compost and, subsequently, your garden soil, potentially stunting plant growth or even making plants unsafe for consumption. Always err on the side of caution and dispose of coal and charcoal ash separately from your compostable waste.
2. Pet Waste (Cats & Dogs)
Unlike herbivore manure from animals like cows or horses, the waste from household pets such as cats and dogs should never be added to your home compost pile. This is primarily due to the potential presence of dangerous pathogens, including bacteria like E. coli and salmonella, as well as parasites like toxoplasmosis (especially prevalent in cat feces). These disease-causing organisms can survive the composting process if the pile doesn’t reach consistently high temperatures, posing a significant health risk to humans and potentially spreading diseases to your garden and food crops. While commercial composting facilities might be equipped to handle pet waste safely at higher temperatures, it’s best to avoid it in your backyard setup.
3. Heavily Dyed or Glossy Paper
While plain paper, like newspaper or shredded office paper, can be an excellent source of carbon for your compost, colored paper or glossy magazines should generally be avoided. The dyes used in brightly colored paper, as well as the inks and coatings found on glossy paper, can contain heavy metals and other chemicals that you don’t want to introduce into your organic compost. These substances can be harmful to soil microorganisms and may contaminate your garden. Stick to unbleached, undyed paper products for the safest composting practices.
4. Garden Lime (Calcium Hydroxide)
Adding lime directly to your compost pile can disrupt the delicate microbial balance essential for decomposition. Lime, which is highly alkaline, can dramatically increase the pH of your compost, making the environment inhospitable for the beneficial bacteria and fungi that break down organic matter. This can slow down or even halt the composting process. While lime is useful for adjusting soil pH in certain garden applications, it’s best kept separate from your active compost pile. If your compost becomes too acidic, there are other natural ways to balance its pH without resorting to lime.
5. Meat and Meat Scraps
While all organic matter eventually decomposes, adding meat scraps – whether cooked or raw – to your compost pile is strongly discouraged for several reasons. Firstly, meat decomposition is a slow and often odorous process, leading to foul smells that can attract unwanted pests such as rats, raccoons, flies, and other scavengers to your compost bin. Secondly, decomposing meat can harbor harmful bacteria like E. coli and salmonella, posing health risks. These pathogens often thrive in cooler composting environments and may not be eliminated if your pile doesn’t consistently reach and maintain optimal temperatures. Stick to plant-based materials for your home composting efforts.
6. Fats, Oils, and Grease (FOG)
Similar to meat, fats, oils, and greases (FOG) are problematic for most backyard composting systems. They decompose very slowly and can create anaerobic (oxygen-deprived) conditions within the pile, leading to unpleasant odors. Beyond the smell, FOG can attract pests, including rodents and flies, and can also coat other compostable materials, hindering the decomposition process by creating a barrier that prevents microorganisms from effectively breaking down organic matter. It’s best to dispose of cooking oils and greasy residues in the trash or designated recycling programs, rather than introducing them to your compost.
7. Bones
While bones are organic, they are exceptionally dense and take an extraordinarily long time to decompose in a typical home compost pile – often years, even small ones. During this lengthy breakdown period, they can attract pests that are drawn to the residual meat and marrow. If you’re determined to compost bones, they would ideally need to be crushed into a fine powder or bone meal, which requires specialized equipment not commonly found in household kitchens. For most composters, it’s more practical and hygienic to discard bones with regular waste.
8. Diseased or Pest-Infested Plants
Adding plants suffering from fungal, bacterial, or viral diseases, or those infested with pests, to your compost pile is a risky endeavor. Unless your compost consistently reaches and maintains high temperatures (at least 135-140°F or 57-60°C for several days), the pathogens and pest eggs are likely to survive. Once the compost is used in your garden, these diseases and pests can then be reintroduced, potentially infecting healthy plants and spreading problems throughout your landscape. It’s much safer to bag diseased plant material and dispose of it with your regular trash to prevent further spread.
9. Fresh Sod or Turf
While grass clippings are a fantastic “green” material for composting, adding large pieces of fresh sod or turf can be problematic. The primary issue is that sod often contains viable grass and weed seeds, along with roots. Unless your compost pile is actively hot and consistently reaches temperatures high enough to sterilize these seeds (around 130-160°F or 54-71°C), they can survive and sprout within your compost pile, effectively turning it into a miniature lawn. If you must compost sod, shake off as much soil as possible, break it into very small pieces, and ensure your pile is actively heating. Otherwise, it’s generally better to let sod dry out and die off completely before adding it, or use it for sheet mulching directly in garden beds.
10. Dairy Products (Milk, Yogurt)
Dairy products, including milk, yogurt, and other fluid dairy, are best kept out of your compost bin. Like meat and grease, they decompose anaerobically, creating unpleasant odors that can attract pests like rodents and flies. While they do contain some nutrients like calcium, the drawbacks of foul smells and pest attraction generally outweigh the minimal benefits for a typical home composting setup. If you have small amounts of liquid dairy, consider diluting it and adding it directly to plants as a gentle fertilizer, or simply dispose of it properly to avoid inviting critters to your compost pile.
11. Cheese and Other Solid Dairy
Similar to liquid dairy, solid dairy products like cheese, butter, and cream cheese should be excluded from your compost. They contain fats and proteins that break down slowly, generate strong odors, and act as a strong magnet for pests. The decomposition of these items can also contribute to a slimy, unappealing consistency in your compost pile. For a clean, efficient, and odor-free composting experience, it’s advisable to avoid all forms of dairy.
12. Wild Bird Droppings (Caution Recommended)
While poultry manure (from chickens, for example) is an excellent compost additive when properly managed, wild bird droppings come with some caveats. They can indeed provide nitrogen, but wild birds often consume seeds, and these seeds may pass through their digestive system intact, potentially introducing unwanted weeds into your compost and subsequently into your garden. Additionally, wild bird droppings could carry diseases. If you choose to add them, ensure your compost pile consistently reaches high temperatures to kill off any weed seeds or pathogens, and use them sparingly.
13. Walnut Leaves, Hulls, and Branches
Unlike many other nuts and plant materials, black walnut trees (and to a lesser extent, English walnuts) produce a natural chemical called juglone. Juglone is allelopathic, meaning it inhibits the growth of many other plants. This chemical can persist in walnut leaves, hulls, and branches even after they’ve decomposed. Adding these materials to your compost means you could be introducing juglone into your finished compost, which might then harm sensitive plants in your garden, such as tomatoes, peppers, blueberries, and certain fruit trees. It’s safer to avoid composting any parts of walnut trees.
14. Large Quantities of Cooking Oils
While small amounts of residual oil on food scraps might be acceptable, pouring significant quantities of cooking oils (vegetable oil, olive oil, etc.) into your compost is not recommended. As mentioned with other fats, oils break down very slowly, can become rancid and odorous, and may attract pests. They also create a greasy barrier that can inhibit the breakdown of other materials by coating them and preventing microbial access. For sustainable disposal, many municipalities offer recycling programs for used cooking oil, or you can solidify small amounts and dispose of them with regular trash.
15. Chemical Pesticides or Herbicides
It goes without saying that synthetic chemical pesticides, herbicides, or fertilizers should never be added to your compost pile. The purpose of composting is to create an organic, natural soil amendment. These chemicals can kill the very microorganisms (bacteria, fungi, worms) that are essential for the composting process. Furthermore, residues of these chemicals can persist in the finished compost, which would then be transferred to your garden, potentially harming your plants, the soil ecosystem, beneficial insects, and even human health if used on edible crops. Keep your compost pure and organic.
16. Large Quantities of Onion or Garlic Scraps
While small amounts of onion and garlic peels or scraps won’t harm your compost, larger quantities can be slow to break down. The strong compounds in onions and garlic can also deter some beneficial compost organisms and may produce a pungent odor during decomposition that could attract certain pests. If you do add them, chop them finely and bury them deep within an active, hot pile to encourage faster breakdown and minimize odors. However, for a balanced and odor-free compost, consider limiting these pungent additions.
17. Citrus Peels and Fruits
Similar to onion and garlic scraps, citrus peels (from oranges, lemons, limes, grapefruits) tend to break down very slowly due to their tough, waxy rinds and natural oils (like limonene) which are antimicrobial. These antimicrobial properties can actually inhibit the activity of beneficial microorganisms in your compost pile, potentially slowing down the entire decomposition process. Large quantities can also attract fruit flies. If you wish to compost citrus, cut the peels into very small pieces and add them sparingly, ensuring they are well-mixed into a hot, active pile.
18. Cigarette Butts, Cigar Stubs, and Tobacco Products
Absolutely avoid adding cigarette butts, cigar stubs, or any tobacco products to your compost. These items contain numerous toxic chemicals, including nicotine (a natural pesticide but toxic in large quantities), tar, and heavy metals, which are highly detrimental to soil health and plant life. The filters in cigarette butts are made of cellulose acetate, a type of plastic that is not biodegradable and will persist in your compost. Introducing these contaminants negates the purpose of creating healthy, organic compost for your garden. Always dispose of tobacco waste in the trash.
The Green List: Over 80 Items You CAN Compost for Rich Garden Soil
19. Alfalfa Meal or Hay
Alfalfa is a powerhouse “green” ingredient for your compost pile, rich in nitrogen, phosphorus, and potassium, along with many trace minerals. Whether you add it as fresh hay, dried alfalfa, or in meal form, it acts as a fantastic activator, accelerating the decomposition process and boosting the nutrient content of your finished compost. For optimal breakdown, it’s best to chop or shred alfalfa hay into smaller pieces before adding it, especially if you’re looking to quickly build a hot compost pile. Its rapid decomposition helps feed the essential microorganisms in your bin.
20. Algae and Pond Scum
If you have access to freshwater ponds or even marine environments (and are permitted to collect it), algae is a wonderful “green” material to add to your compost. It’s highly rich in nitrogen, as well as a variety of trace minerals, making it a valuable nutrient booster for your compost pile. Just be sure to rinse off any excessive salt if collecting from the ocean, and check for any aquatic invasives if collecting from freshwater sources. Algae decomposes quickly, adding moisture and accelerating the breakdown of other materials.
21. Untreated Wood Ash (from fireplaces/bonfires)
Wood ashes from clean-burning, untreated wood (like from a fireplace or bonfire) can be a beneficial addition to your compost, but moderation is key. Wood ash is alkaline and rich in potassium, calcium, and magnesium, which can neutralize acidic soil and provide valuable micronutrients. However, adding too much can drastically increase the pH of your compost pile, inhibiting microbial activity. It’s best to add wood ash sparingly, sprinkling thin layers and mixing it in, rather than dumping large amounts. Avoid ash from charcoal, treated lumber, or composite wood products, as these can contain harmful chemicals.
22. Banana Peels
Banana peels are a fantastic “green” addition, renowned for their high potassium content, an essential nutrient for plant growth and fruit development. They also contribute phosphorus, calcium, and magnesium. To help them break down more quickly, especially in cooler compost piles, it’s highly recommended to chop or tear banana peels into smaller pieces before adding them. This increases their surface area, allowing microorganisms to work their magic more efficiently. Burying them deeper in the pile can also discourage fruit flies.
23. Kitchen Rinse Water & Cooking Liquids (Unsalted)
Don’t let nutrient-rich water go down the drain! Water used for boiling pasta, vegetables, or eggs, as long as it’s unsalted and cooled, can be a valuable addition to your compost pile. This “kitchen rinse water” helps to maintain the essential moisture levels in your compost, which is crucial for microbial activity. Additionally, it often contains trace amounts of nutrients like calcium (from eggshells), magnesium, and starches from vegetables, further enriching your compost. It’s a simple yet effective way to recycle resources and hydrate a dry pile, especially during warmer months.
24. Buckwheat Straw and Hulls
Buckwheat straw and its hulls are excellent “brown” materials, providing a significant source of carbon to your compost pile. Carbon-rich materials are vital for balancing the nitrogen-rich “greens” and creating the ideal environment for decomposition. Buckwheat breaks down relatively quickly compared to other straws, especially if chopped or shredded into smaller pieces. Its inclusion helps improve the texture and aeration of your finished compost, making it an ideal soil amendment. It’s also known for not introducing weed seeds, which can be a concern with other types of straw.
25. Plain Cardboard
Untreated, plain cardboard (like shipping boxes or toilet paper rolls) is a fantastic “brown” carbon source for your compost. It helps absorb excess moisture, prevents compaction, and provides structure for good aeration. Always remove any plastic tape, labels, or wax coatings before adding cardboard. To significantly speed up its decomposition, tear or shred the cardboard into small pieces and moisten it thoroughly before incorporating it into your pile. Avoid heavily printed or glossy cardboard, as the inks and coatings can contain undesirable chemicals, as mentioned earlier.
26. Clover
Clover, especially green clover, is a superb “green” material for composting due to its high nitrogen content. As a legume, clover fixes atmospheric nitrogen into the soil, making it readily available for other plants and for the microbial life in your compost pile. Adding clover scraps or even spent clover cover crops can significantly boost the nitrogen levels, acting as a natural compost activator and accelerating the decomposition of carbon-rich “brown” materials. Ensure it’s chopped into manageable pieces for faster breakdown.
27. Unused, Organic Cat Litter (Wood/Paper Based)
While used cat litter should generally be avoided (due to potential pathogens, as discussed earlier), unused and truly organic cat litter made from materials like pine, cedar, corn, or recycled paper can be a decent “brown” carbon source. It helps absorb moisture and adds bulk. However, it’s crucial that it’s completely unused and free from any added fragrances, chemicals, or clumping agents which can be harmful. Even then, its primary value is as a filler or absorbent material, and it’s less nutrient-dense than other browns.
28. Cocoa Hulls
Often available from garden suppliers or as a byproduct of chocolate production, cocoa hulls are a wonderful “green” compost ingredient, providing a rich source of nitrogen and trace minerals. They also have a pleasant, mild chocolatey aroma that can help mask other compost odors. To ensure quick decomposition and release of nutrients, chop or crush the cocoa hulls into smaller pieces before adding them to your pile. Their fine texture also helps to improve the overall consistency of your finished compost.
29. Coffee Grounds and Paper Filters
Coffee grounds are a classic and highly beneficial “green” component for any compost pile. Despite their dark color, they are rich in nitrogen, along with phosphorus, potassium, magnesium, and copper. They also contain beneficial microbes that can help activate your compost. Used paper coffee filters are also perfectly compostable, adding carbon and breaking down quickly. Together, they help create a nutrient-dense compost and are excellent for encouraging worm activity. Always ensure they are thoroughly mixed into the pile to prevent clumping and maintain aeration.
30. Corn Stalks and Cobs
Corn stalks and cobs are excellent “brown” carbon materials, but they are dense and can take a long time to break down. To facilitate decomposition, it’s highly recommended to chop or shred them into smaller pieces (1-2 inches) before adding them to your compost. If your compost pile is consistently hot and active, they will eventually decompose. These bulky additions help create air pockets within the pile, improving aeration and preventing compaction. They contribute organic matter that slowly releases nutrients into your finished compost, enhancing soil structure.
31. Dry Pet Food (Plant-Based)
While generally not a primary compost ingredient, small amounts of leftover dry pet food can be added to the compost, provided it’s primarily plant-based and not a meat-heavy formula. The concern with meat-based pet food is the same as with other meat products: it can attract pests and create foul odors as it decomposes. If you do add dry, plant-based kibble, moisten it and bury it deep within an active pile to encourage quick breakdown and minimize any potential issues. It adds some nitrogen and carbon to the mix.
32. Cowpeas and Other Legume Plant Matter
Cowpeas, like other legumes (such as beans, peas, and alfalfa), are excellent “green” materials for your compost pile because of their high nitrogen content. Leguminous plants have a symbiotic relationship with nitrogen-fixing bacteria in their root nodules, allowing them to capture atmospheric nitrogen. When these plants are added to compost, they release this stored nitrogen, acting as a natural compost accelerator and greatly enriching the final product. Chop them into smaller pieces for faster breakdown and better nutrient distribution.
33. Natural Fiber Dryer Lint
Dryer lint made exclusively from natural fibers like cotton, linen, wool, or rayon can be a surprising but useful “brown” addition to your compost. It’s a source of carbon and helps add bulk. However, it’s crucial to ensure your lint is free from synthetic fibers (polyester, nylon, acrylic) which are essentially plastic and will not biodegrade. Also, avoid lint from heavily dyed or chemically treated fabrics. Moisten the lint before adding it to prevent it from becoming a dry, impermeable mat, and mix it well into the pile.
34. Human and Pet Hair
Yes, even human hair clippings and pet fur (from brushing your dog or cat) can be composted! Hair is rich in nitrogen and protein, acting as a slow-release nitrogen source. While it can take a bit longer to break down due to its protein structure, it will eventually decompose and contribute valuable nutrients. To speed up the process, you can chop hair into shorter pieces or spread it thinly throughout the pile rather than adding it in clumps. It’s a great way to recycle something you might otherwise just throw away.
35. Cotton Bur or Cotton Gin Trash
Cotton bur, a byproduct of cotton ginning, is an exceptionally potent “green” material. It is very high in nitrogen, making it an excellent compost activator, particularly for kickstarting a new pile or reheating a sluggish one. Its rapid decomposition fuels microbial activity, generating heat and accelerating the entire composting process. When using cotton bur, ensure you mix it thoroughly with “brown” materials to maintain a balanced carbon-to-nitrogen ratio and prevent the pile from becoming overly nitrogen-rich, which can lead to ammonia odors. It’s a fantastic resource for serious composters.
36. Eggshells
Eggshells are a fantastic source of calcium carbonate, an essential nutrient for plant cell wall development and overall plant health. While they do break down slowly, crushing or grinding them into smaller pieces before adding them to your compost pile will significantly speed up their decomposition. They also help improve soil structure and can deter slugs and snails in the garden once the compost is applied. Always rinse eggshells before adding them to avoid attracting pests from residual egg matter.
37. Feathers
Feathers, whether from poultry, wild birds, or even old feather pillows, are rich in nitrogen and protein, making them a valuable “green” addition to your compost. Their structure means they can take a little longer to decompose than softer materials. To accelerate their breakdown, it’s best to chop or shred them into smaller pieces if possible. When mixed into an active, hot compost pile, feathers will eventually transform into nutrient-rich organic matter, releasing their nitrogen slowly over time, which is excellent for sustained plant growth.
38. Spent Flowers and Floral Trimmings
After your cut flowers have faded or your garden blooms are past their prime, don’t discard them – compost them! Both fresh and dried flowers, along with their stems and leaves, are excellent organic materials. Fresh flowers contribute nitrogen (“greens”), while dried flowers offer carbon (“browns”). Always remove any non-biodegradable elements like ribbons, floral wire, or plastic decorative pieces. Chopping larger stems and blooms will speed up their decomposition. They add a lovely diversity of organic matter and trace nutrients to your compost.
39. Most Fruit Peels and Scraps
From apple cores to melon rinds (excluding citrus in large quantities, as discussed), most fruit peels and scraps are fantastic “green” additions to your compost pile. They are rich in nitrogen, moisture, and various vitamins and minerals beneficial for soil health. To ensure rapid decomposition and prevent the attraction of fruit flies, it’s essential to chop fruit scraps into small pieces and bury them beneath other materials in an active compost pile. This maximizes surface area for microbial activity and discourages pests.
40. Grass Clippings
Grass clippings are one of the most common and valuable “green” materials for composting. Freshly cut, they are incredibly rich in nitrogen, which is a powerful activator for your compost pile, helping to heat it up and accelerate decomposition. However, it’s important to add grass clippings in thin layers and mix them well with “brown” materials to prevent them from compacting into a slimy, anaerobic, and smelly mat. When dried, grass clippings transform into a “brown” material, providing carbon. Either way, they are a fantastic resource from your lawn!
41. Spent Hops (from Brewing)
For home brewers, spent hops are a fantastic “green” addition to the compost pile. Rich in nitrogen and various trace minerals, they decompose readily and contribute significantly to the nutrient profile of your finished compost. While they are often considered “greens” due to their nitrogen content, they also offer a good amount of organic matter (carbon). Mix them thoroughly into your pile, especially with drier, carbon-rich materials, to ensure even decomposition and prevent any strong lingering odors.
42. Kelp and Seaweed
If you live near the coast, kelp and other seaweeds are exceptional “green” materials for composting. They are incredibly rich in a wide array of trace minerals, including potassium, calcium, magnesium, and iodine, which are highly beneficial for plant health. Seaweeds also provide alginic acid, which improves soil structure. To use them, rinse off any excess salt to prevent salinity issues, and chop them into smaller pieces for faster decomposition. They break down quickly and add a potent boost of nutrients to your compost.
43. Natural Leather Scraps (Untreated)
Surprisingly, small pieces of natural, untreated leather can be composted, though they break down very slowly. Leather is primarily protein (collagen) and will contribute nitrogen over time. However, it’s crucial to ensure the leather is vegetable-tanned or naturally processed and free from synthetic dyes, chrome, or other chemical treatments, which can be harmful to your compost and soil. Shredding or cutting leather into very small pieces (e.g., from old belts, shoes without synthetic soles, or craft scraps) will significantly aid in its eventual decomposition. Bury them deep in an active pile.
44. Leaves (Autumn & Fresh)
Leaves are a cornerstone of any good compost pile, offering a rich source of carbon (“browns”) when dry (like autumn leaves) and a good amount of nitrogen (“greens”) when fresh. They provide essential bulk, improve aeration, and foster a healthy fungal population crucial for decomposition. Shredding or chopping leaves, especially tougher ones like oak, will dramatically speed up their breakdown. You can collect and store dried leaves in bags to use as a carbon source throughout the year, balancing out your nitrogen-rich kitchen scraps.
45. Herbivore Manure (Cows, Horses, Chickens, Rabbits, Sheep, Pigs)
Manure from plant-eating animals is an incredibly valuable “green” addition to your compost, rich in nitrogen, phosphorus, and other essential nutrients. It also introduces a robust population of beneficial microorganisms that kickstart decomposition. Manure from cows, horses, chickens, rabbits, sheep, and pigs are all excellent choices. However, it’s crucial to ensure the manure is well-aged or thoroughly composted before using it in your garden to avoid burning plants with excess nitrogen, or introducing weed seeds that may have passed through the animal’s digestive system. Always allow manure-rich compost to mature for several months to ensure pathogens are eliminated and nutrients are stabilized.
46. Shredded Newspaper
Newspaper is an excellent “brown” carbon material, perfect for balancing out nitrogen-rich kitchen scraps. It helps absorb excess moisture, prevents odors, and adds bulk. Always opt for black and white newspaper, as colored inks can sometimes contain heavy metals (though modern soy-based inks are generally safer). Shredding newspaper into thin strips is crucial for quick decomposition, as large sheets can clump and create anaerobic pockets. Moisten it before adding to help with breakdown and prevent it from flying away.
47. Nutshells (excluding walnuts) and Peanut Hulls
Most nutshells (like almonds, pecans, hazelnuts, and pistachios) and peanut hulls are wonderful “brown” sources of carbon for your compost. They add structure and bulk, improving aeration within the pile. However, they are generally tough and dense, meaning they will take a long time to break down. Crushing them into smaller pieces will significantly speed up this process. As mentioned previously, avoid black walnut shells due to the allelopathic chemical juglone. These tough materials contribute to the long-term health and structure of your finished compost.
48. Oak Leaves
Oak leaves are a valuable “brown” carbon source, similar to other deciduous leaves. While they are a bit tougher and more acidic than some other leaves (due to their tannin content), they are perfectly compostable. To encourage faster decomposition, it’s highly recommended to shred or chop them before adding them to your pile. Their acidity will generally be neutralized by other materials in a balanced compost pile. Oak leaves contribute rich organic matter and help create a beautiful, dark, crumbly compost.
49. Untreated Sawdust and Wood Shavings
Sawdust and wood shavings from untreated, raw wood (not kiln-dried, pressure-treated, or particle board) are excellent “brown” carbon sources. They are particularly useful for absorbing excess moisture and odors. However, because they are very high in carbon and low in nitrogen, they can temporarily deplete nitrogen from the compost pile as they break down. To prevent this, add sawdust in thin layers, mix it thoroughly with nitrogen-rich “green” materials, and ensure adequate moisture. This balance will help speed up decomposition and create healthy compost.
50. Plain Paper Products
Beyond newspaper and cardboard, many other plain paper products can be composted. This includes non-glossy office paper, paper bags, paper towel and toilet paper rolls (removed from plastic), and plain paper napkins. These items are all excellent “brown” carbon sources. As with other paper products, shredding them into smaller pieces is essential for faster decomposition. Always ensure they are clean, free of plastic coatings, heavy inks, or any food residues that might attract pests (like grease). They help absorb moisture and provide bulk for good aeration.
51. Vetch (Legume Plant)
Vetch, a cover crop belonging to the pea family, is a highly beneficial “green” component for composting. Like clover and cowpeas, vetch is a nitrogen-fixing legume, meaning it significantly enriches your compost with nitrogen and other valuable nutrients. When added fresh or as chopped-up plant matter, it acts as a powerful compost activator, promoting rapid microbial growth and heat generation. Incorporating vetch will help create a nutrient-dense compost that will greatly benefit your garden soil structure and fertility.
52. Used Tea Leaves and Paper Tea Bags
Just like coffee grounds, used tea leaves are fantastic “green” additions to your compost pile. They are rich in nitrogen, tannins, and other beneficial organic compounds. Paper tea bags (ensure they are not made of synthetic mesh or contain plastic staples) are also perfectly compostable. Tearing open the tea bags to release the leaves or simply shredding the entire bag will help them decompose faster. They contribute to a rich, dark compost and are excellent for encouraging earthworm activity.
53. Peat Moss (Use Sustainably Sourced)
Peat moss, while an excellent soil amendment for improving drainage and water retention, and providing carbon, is a “brown” material that can be added to compost. However, its use is debated due to environmental concerns regarding its harvesting from peat bogs, which are unique ecosystems and carbon sinks. If you choose to use peat moss, ensure it is sustainably sourced. When added to compost, it helps create a consistent texture and improves the final product’s ability to hold moisture. It breaks down slowly, so it contributes long-term organic matter.
54. Pine Cones and Pine Needles
Pine needles and pine cones are excellent “brown” materials, providing a significant source of carbon and improving the aeration of your compost pile. While they are somewhat acidic and take longer to break down due to their waxy coating and resinous nature, a balanced compost pile will generally neutralize their acidity. To speed up decomposition, it’s highly beneficial to shred pine needles and crush pine cones into smaller pieces. They add wonderful texture and a pleasant scent to your compost, mimicking forest floor decomposition.
55. All Vegetable Scraps (Raw or Cooked)
Virtually all raw or cooked vegetable scraps are ideal “green” additions to your compost pile (excluding diseased plants or excessively greasy cooked vegetables). From broccoli stems and carrot peels to lettuce trimmings and potato skins, these kitchen discards are rich in nitrogen, moisture, and a wide array of vitamins and minerals. Composting vegetable scraps is one of the easiest and most effective ways to reduce household food waste and generate nutrient-dense compost for your garden. Chop larger pieces to accelerate breakdown and bury them deep in the pile to prevent odors and pests.
56. Garden Weeds (Seed-Free or Hot Composted)
Most weeds can be composted, offering valuable “green” material rich in nitrogen and organic matter. However, a critical distinction must be made: avoid composting weeds that have gone to seed unless you are running a consistently hot compost pile (maintaining 130-160°F or 54-71°C for several days). Otherwise, you risk spreading viable weed seeds throughout your garden when you apply the finished compost. Similarly, avoid weeds with invasive root systems (like bindweed) that can re-sprout. For most weeds, remove them before they seed, chop them, and mix them into an active pile.
57. Wheat Straw
Wheat straw is a classic and highly effective “brown” carbon source for composting. It provides excellent aeration, prevents compaction, and helps balance out nitrogen-rich “green” materials. Wheat straw breaks down relatively slowly, adding long-term organic matter and structure to your compost. It’s often used as bedding for animals, which then becomes a convenient compost ingredient (manure-straw mix). Chop it into smaller pieces to speed up decomposition, and ensure it’s well-moistened and mixed throughout the pile.
58. Herbs and Spices
Leftover, dried, or past-their-prime herbs and spices are perfectly safe and beneficial to add to your compost pile. They typically break down very quickly due to their fine texture and small size. While they may not add significant bulk, they contribute a diverse range of trace minerals and organic compounds, enriching the microbial life in your compost. Plus, it’s a great way to dispose of old spices from your pantry rather than throwing them in the trash.
59. Unused or Expired Seeds
If you have old packets of seeds that are past their prime or simply won’t be planted, don’t just toss them. They can be added to your compost pile! Seeds are excellent sources of carbon and some nitrogen. To prevent them from sprouting in your compost or garden, it’s advisable to crush them or ensure your compost pile consistently reaches high temperatures. Alternatively, you can soak them in water for a few days to encourage germination, then add the sprouted seeds to the compost.
60. Avocado Pits and Cherry Pits
Fruit pits, such as those from avocados and cherries, are entirely compostable, but be aware that they are quite dense and will take a considerable amount of time to fully break down – often many months or even a year. While they don’t offer immediate nutrient release, they do contribute long-term organic matter and improve soil structure. If you’re patient, simply add them whole. For faster decomposition, you could try cracking them open or chopping them, though this can be difficult.
61. Bamboo Skewers and Chopsticks (Untreated)
Leftover bamboo skewers and chopsticks from takeout (as long as they are natural, untreated bamboo and not coated with wax or plastic) are compostable. Bamboo is a fibrous woody material that provides carbon. Since they are quite sturdy, it’s essential to break or chop them into smaller pieces (2-3 inches) to help them decompose more efficiently. They will still take a while to break down fully, but they contribute valuable organic matter to your compost over time.
62. Used Paper Napkins and Paper Towels (Unbleached & Uncontaminated)
Used paper napkins and paper towels are excellent “brown” materials for your compost pile, providing carbon and helping to absorb excess moisture. Ensure they are unbleached and have not been used to clean up harsh chemicals, grease, or animal products (which can attract pests). If they’re just from wiping mouths or drying hands, they’re perfect. Tearing them into smaller pieces will aid in faster decomposition. They are a simple and effective way to divert waste from your landfill.
63. Natural Fabric Scraps (Cotton, Linen, Wool)
Fabric scraps made from 100% natural fibers like cotton, linen, hemp, or wool are compostable. They are a good source of carbon and will eventually break down, though this can take some time. It’s crucial to avoid synthetic fabrics (polyester, nylon, rayon, spandex), which are plastic-based and will not decompose. To speed up the process for natural fabrics, cut or shred them into small pieces. They add texture and organic matter to your compost, reducing textile waste.
64. Pencil Shavings (Untreated Wood)
Pencil shavings, derived from natural wood and graphite, are perfectly compostable “brown” material. They provide carbon and add a pleasant woody aroma to your pile. As long as the pencils are made from untreated wood and not plastic-coated or heavily painted, their shavings are safe to add. They break down relatively quickly, especially if mixed in with other materials, contributing fine organic matter to your finished compost.
65. Burlap (Natural Jute or Hemp)
Burlap made from natural fibers like jute or hemp is fully compostable and serves as an excellent “brown” carbon source. It’s often used in gardening for protection or as root balls, making it a common item to compost. To ensure proper decomposition, tear or cut the burlap into smaller strips. It can take some time to break down due to its fibrous nature, but it significantly adds to the organic matter and structure of your compost. Always check that it’s not synthetic burlap, which is plastic.
66. Natural Fiber Rope and Twine
Similar to burlap, rope and twine made from natural fibers such as cotton, jute, hemp, or sisal are compostable. These materials contribute carbon and can help maintain aeration within the pile. However, it is absolutely essential to ensure they are free from any synthetic plastics, which will not break down. To facilitate decomposition, cut the rope or twine into short pieces (a few inches long) as they can be quite tough and slow to degrade otherwise. Bury them within an active compost pile.
67. Stale or Spoiled Wine and Beer
Don’t pour stale beer or spoiled wine down the drain – add it to your compost! These liquids provide moisture and a boost of beneficial microorganisms, particularly yeast and bacteria, which can accelerate the decomposition process. While not significant sources of bulk nutrients, their microbial content acts as a natural compost activator. Add them in moderation to avoid making your pile too wet, and ensure they are well-absorbed by drier materials to prevent attracting pests or creating anaerobic conditions.
68. Broccoli Stems and Leaves
Beyond being a healthy addition to your diet, all parts of broccoli – including stems, florets, and leaves – are fantastic for your compost pile. They are rich in nitrogen, fiber, and importantly, sulfur, which is a vital micronutrient for plant growth and disease resistance. Chop tough broccoli stems into smaller pieces to ensure they break down efficiently. These “green” scraps contribute significantly to the nutrient density and overall health of your compost, promoting vigorous plant development in your garden.
69. Apple Cores and Peels
Apple cores, peels, and even slightly bruised apples are perfect “green” additions to your compost. They are rich in moisture, nitrogen, and various micronutrients that support plant health and even aid in seed development. To ensure quick decomposition and avoid attracting fruit flies, chop apple scraps into small pieces and bury them within the warmer, active core of your compost pile. They break down readily and contribute to a rich, dark finished compost.
70. Tomato Scraps (Non-Diseased)
Tomato skins, pulp, and even whole overripe, non-diseased tomatoes are excellent “green” additions to your compost. They are rich in nitrogen, moisture, and important trace minerals like manganese, which is crucial for photosynthesis and plant growth. Just be mindful of adding large quantities of tomato seeds, as they can sometimes sprout in your compost. Chopping tomatoes into smaller pieces and burying them deep within the pile will speed up decomposition and minimize any potential issues.
71. Potato Peels and Rotten Potatoes (Non-Diseased)
Potato peels and any potatoes that have gone soft or rotten (as long as they are not diseased with late blight or other serious issues) are excellent “green” compost materials. They are packed with moisture, nitrogen, and particularly rich in copper, a micronutrient vital for enzyme activity in plants. Cut large potatoes into smaller chunks to ensure faster decomposition. Be cautious of “sprouting” potatoes, as the sprouts can sometimes continue to grow in cooler compost piles. Bury them deep for best results.
72. Stale Bread and Cereals
Stale bread, expired cereals (plain, not heavily sugared or frosted), and other plain baked goods are excellent “brown” carbon sources for your compost. They break down relatively quickly and provide readily available energy for compost microorganisms. However, it’s essential to add them in moderation and bury them deep within the pile to prevent attracting pests like rodents. Avoid items with excessive amounts of dairy, meat, or large quantities of sugar, as these can cause odor problems and attract unwanted visitors. Break larger pieces into smaller ones for faster decomposition.
73. Cooked Rice and Pasta (Plain)
Plain cooked rice and pasta, without sauces, oils, or meat, can be added to your compost pile. They are good sources of carbon and readily digestible by microorganisms. However, like bread, they should be added in moderation and buried deep to prevent odors and attraction of pests. Cooked starchy foods break down much faster than raw grains. If left exposed, they can quickly grow mold and attract unwanted visitors, so always ensure they are well-covered by other compost materials.
74. Dead Houseplants (Non-Diseased)
When your beloved houseplants reach the end of their life due to natural causes, overwatering, or neglect, they can be safely added to your compost pile. They provide valuable “green” and “brown” organic matter. However, as with garden plants, it’s crucial to avoid composting any houseplants that have died from or show signs of disease (fungus, pests, etc.) to prevent spreading these issues. Remove them from their pots and break up the root ball before adding them to ensure efficient decomposition.
75. Plain Candy and Sugary Scraps (in moderation)
Small quantities of plain candy (e.g., hard candies, jelly beans without artificial dyes) and other sugary scraps can be added to your compost. Sugar acts as a quick energy source for the microorganisms, potentially speeding up decomposition. However, moderation is key. Large amounts of sugar can attract pests like ants and rodents, and can also lead to anaerobic (smelly) conditions. Always bury sugary items deep within the pile and ensure they are well-mixed with other materials to mitigate these risks. Avoid anything with artificial colors, flavors, or wrappers.
76. Pet Fur (Dog, Cat, Rabbit)
Pet fur, whether from grooming your dog, cat, or rabbit, is a fantastic “green” material rich in nitrogen and protein, similar to human hair. It will break down over time, contributing valuable organic matter and nutrients to your compost. To aid decomposition, try to spread fur thinly throughout the pile rather than adding it in large clumps, which can mat together and slow down the process. It’s an excellent way to recycle a common household waste product.
77. Plain Oats and Oatmeal
Uncooked or cooked plain oats and oatmeal are perfectly compostable. They are a good source of carbon and provide readily available energy for the microbial community in your compost. As with other starchy foods, it’s best to add them in moderation and bury them deep within the pile to prevent attracting pests or developing odors. They break down relatively quickly, adding to the overall organic richness of your compost.
78. Cardboard Egg Cartons
Plain cardboard egg cartons (not styrofoam or plastic ones) are an excellent “brown” carbon source for your compost. They add structure, help absorb moisture, and create air pockets. While they can be a bit slow to break down if added whole, tearing them into smaller pieces will significantly accelerate the process. Always remove any labels or plastic tape if present. Composting egg cartons is a simple way to recycle packaging waste and provide valuable bulk to your compost pile.
79. Dry Pasta (Plain)
Expired or unused dry pasta (plain, without sauces or flavorings) can be added to your compost. It’s a carbon-rich “brown” material that will eventually break down. While cooked pasta breaks down faster, dry pasta will also decompose, though it may take a bit more time. To speed up the process, you can break larger pieces into smaller ones or soak them briefly. As with other starchy foods, bury them deep in the pile to prevent attracting pests.
80. Natural Wine Corks
Natural corks, made from the bark of cork oak trees, are entirely compostable. They are a “brown” carbon source and will eventually decompose, though their dense structure means they will take a relatively long time. To accelerate decomposition, chop or crumble the corks into smaller pieces. Avoid synthetic corks made from plastic, which are not biodegradable. Composting natural corks is a great way to repurpose them and add slow-release organic matter to your compost.
81. Natural Potpourri
If your potpourri is made from natural, dried plant materials (like dried flowers, leaves, wood chips, and spices) and is free from synthetic fragrances, artificial dyes, or plastic components, it can be added to your compost pile. It will contribute carbon and some organic matter. However, be mindful that strong artificial fragrances can sometimes deter beneficial microorganisms. Ensure it’s genuinely natural before adding, and mix it well into the pile. It’s a good way to dispose of old, faded potpourri.
82. Fish Scraps (with caution)
Fish scraps, including bones and entrails, are incredibly rich in nitrogen, phosphorus, and trace minerals, making them a potent “green” compost material. They can greatly boost nutrient content. However, they decompose rapidly and can produce strong, unpleasant odors that attract pests (rodents, raccoons, flies). For this reason, it’s crucial to bury fish scraps deep within a large, active, and hot compost pile, surrounded by plenty of “brown” materials to absorb odors and discourage pests. For smaller operations, using a sealed digester or bokashi system might be a better option for fish waste.
83. Real Cellophane (Cellulose-based)
True cellophane, which is made from regenerated cellulose (wood pulp), is biodegradable and can be composted. It will break down over time, contributing organic matter. However, it is often confused with plastic films, which are not compostable. To test if it’s real cellophane, try crumpling it – true cellophane will often stay crumpled, while plastic will spring back. Also, you can try tearing it – real cellophane tears easily. Ensure it’s clean and free of glues or dyes before adding it to your compost pile.
84. Expired Jelly and Jam (in moderation)
Expired or moldy jelly and jam, as long as they don’t contain excessive artificial ingredients, can be added to your compost in moderation. Their high sugar content acts as a quick energy source for microbes, helping to activate the pile. However, too much sugar can attract pests and lead to anaerobic conditions. Always bury them deep within the compost, surrounded by “brown” materials, to absorb moisture and prevent pest issues. They will break down quickly, contributing to the “green” aspect of your compost.
85. Flour and Starch (Plain)
Expired or spoiled flour (wheat, corn, rice, etc.) and other plain starches are highly compostable “brown” materials. They provide an excellent source of carbon and act as a fast-acting energy boost for the microbial community, accelerating decomposition. However, it’s crucial to add them in moderation and mix them well into the compost pile. If added in large, unmixed clumps, flour can become a pasty, anaerobic mess, hindering decomposition and potentially attracting pests. Spread it thinly or pre-mix with water before adding.
86. Plain Jell-O and Gelatin (in moderation)
Plain gelatin and Jell-O (without excessive artificial colors, flavors, or fruit pieces) can be added to your compost in small amounts. Gelatin is derived from collagen, providing a protein-rich “green” component that contributes nitrogen. Jell-O, being largely sugar, will act as a microbial stimulant. As with other sugary or proteinaceous items, moderation is key, and they should be buried deep within an active pile to prevent odors and attraction of pests. They break down quite quickly, adding to the diversity of organic matter.
87. Shellfish Shells (Mussels, Oysters, Crab, Shrimp)
Shells from mussels, oysters, crabs, lobster, and shrimp are entirely compostable and a fantastic source of calcium carbonate and chitin, which can deter nematodes and improve soil health. However, like eggshells and bones, they are very tough and will take a long time to break down – often many months or even years. Crushing them into smaller pieces will significantly speed up this process. Ensure they are thoroughly rinsed to remove any residual meat or strong odors that could attract pests, then bury them deep in your compost pile. They provide long-term soil benefits.
88. Popcorn Kernels (Plain)
Unpopped or stale popcorn kernels are compostable “brown” material. They are a good source of carbon. As with other starchy grains, it’s best to add them plain – without excessive butter, oil, salt, or artificial flavorings, which can attract pests and slow decomposition. While they may take a little longer to break down than softer kitchen scraps, they will eventually decompose and contribute organic matter. Bury them deep in the pile to encourage breakdown and prevent any attraction issues.
89. Tofu and Tempeh (Plain)
Plain tofu and tempeh, made from soybeans, are excellent “green” additions to your compost pile. They are rich in nitrogen and protein, providing a significant boost to microbial activity. Ensure they are plain, without heavy oils, sauces, or meat ingredients, which could attract pests. Chop them into smaller pieces to accelerate their breakdown, and bury them deep within an active compost pile. They decompose relatively quickly, contributing to a nutrient-rich compost that will benefit your garden.
90. Plant-Based Milks (Soy, Rice, Almond, Oat)
Unlike dairy milk, plant-based milks such as soy, rice, almond, or oat milk are generally safe to add to your compost pile, especially if they are expired or spoiled. They are primarily water and plant solids, making them a “green” material that provides moisture and some nutrients. They tend to break down faster than dairy milk and are less likely to attract pests or produce strong odors, provided they are added in moderation and mixed well into the pile. They can help keep your compost moist and active.
91. Natural Chewing Gum (Caution)
This is a tricky one. While traditional chewing gum was once made from natural chicle (a tree sap) and could theoretically compost, most modern chewing gums are made from synthetic rubber bases, plastics, and artificial sweeteners/flavorings. These synthetic components will not break down in your compost and will remain as microplastics. Therefore, unless you are absolutely certain your gum is 100% natural and biodegradable (which is rare), it’s best to avoid adding chewing gum to your compost and dispose of it in the trash instead. The original statement might be outdated.
92. Flat Soda and Carbonated Water
Flat or expired soda and plain carbonated water can be added to your compost pile. While they don’t provide a significant nutrient boost, they primarily contribute moisture and some sugar (in the case of soda) which can act as a quick energy source for microorganisms, helping to activate the pile. Add them in moderation to avoid oversaturating the compost, and ensure they are absorbed by drier materials. They are generally harmless and a way to repurpose old beverages.
93. Aquarium Plants and Water (Freshwater)
Expired or trimmed freshwater aquarium plants, along with the nutrient-rich water from water changes, are excellent “green” additions to your compost. The plants provide nitrogen and organic matter, while the water contains beneficial microbes and trace nutrients that help activate the compost pile and provide essential moisture. Avoid adding saltwater aquarium contents, as the salt could harm soil organisms. It’s a fantastic way to recycle resources from your aquarium and enrich your compost.
94. Natural Latex Balloons
Natural latex, derived from rubber trees, is biodegradable and can be composted. So, if you have natural latex balloons (not Mylar or synthetic rubber), they can eventually break down in your compost. However, they can take a significant amount of time due to their resilience. It’s important to differentiate them from synthetic rubber or plastic balloons, which are not compostable. To aid decomposition, cut the latex into small pieces. While compostable, they aren’t the most efficient addition.
95. Wool Scraps and Old Woolen Garments
Natural wool, whether processed (like an old sweater) or unprocessed (like raw sheep fleece), is an excellent “green” material for composting. Wool is rich in nitrogen and proteins, and it decomposes slowly, providing a steady release of nutrients. To speed up its breakdown, cut woolen items into smaller pieces. Avoid synthetic blends or chemically treated wool. Wool also helps improve the texture of your compost and can aid in water retention. It’s a wonderful way to recycle worn-out woolens.
96. Christmas Trees and Greenery (Untreated)
After the holidays, your natural Christmas trees, wreaths, and garlands (stripped of all decorations, tinsel, and stands) can be excellent “brown” additions to your compost pile. They provide a significant amount of carbon and woody material. However, they are bulky and dense, so chipping or shredding them into smaller pieces is essential for efficient decomposition. If you don’t have a chipper, many municipalities offer Christmas tree recycling programs that produce mulch. They break down slowly, enriching your compost with long-term organic matter.
97. Halloween Pumpkins and Gourds
Don’t let your Halloween decorations go to waste! Spent pumpkins and gourds are fantastic “green” additions to your compost pile. They are rich in moisture, nitrogen, and various micronutrients. To facilitate quick decomposition, chop them into smaller pieces and remove any candles or artificial decorations. Bury them deep in your pile to prevent attracting pests. They break down quickly, adding a significant boost of organic matter and nutrients, making a wonderful contribution to your garden soil for the next season.
98. Dust Bunnies and Floor Sweepings (Natural Origin)
Yes, even the dust bunnies from under your bed and floor sweepings can be composted, provided they are primarily composed of natural materials like human hair, pet fur, natural fiber lint, and soil particles. They offer a mixed source of carbon and nitrogen. Avoid adding sweepings if they contain excessive amounts of synthetic fibers (plastics), chemicals from cleaning products, or heavy metals. They contribute fine organic matter and are an easy way to recycle household debris that would otherwise go to the landfill.
99. Dead Insects (Non-Pesticide Related)
While it might seem a bit unusual, dead insects – like flies, moths, or garden pests you’ve hand-picked – are perfectly compostable. They are a source of protein and nitrogen, contributing to the “green” components of your pile. Just ensure they haven’t been killed with chemical pesticides, as those residues would be detrimental to your compost. Burying them deep in the pile will ensure they decompose discreetly and efficiently, returning their organic matter to the soil cycle.
100. Natural Glues and Pastes (Starch-based)
Only natural, starch-based glues or pastes (like those made from wheat, cornstarch, or cellulose, often used in school or for paper crafts) are compostable. These types of glues are organic and will readily break down, providing carbon. However, the vast majority of modern adhesives, including super glue, wood glue, hot glue, and many craft glues, are synthetic, plastic-based, and contain chemicals that are not biodegradable and could harm your compost. Always check the ingredients to ensure it’s a natural, non-toxic, and truly compostable adhesive before adding it.
And there you have it – a comprehensive guide to over 100 items you can and cannot compost! This detailed list aims to empower you with the knowledge needed to maintain a thriving compost pile, transforming your kitchen and yard waste into valuable organic matter for your garden. While the sheer number of items might seem daunting at first, remember that successful composting is more about balance and understanding a few core principles than memorizing every single item.
By consciously choosing what goes into your compost, you’re not only enriching your soil with essential nutrients, promoting healthier plant growth, and boosting biodiversity in your garden, but you’re also playing a crucial role in waste reduction and environmental stewardship. Every scrap diverted from the landfill is a step towards a more sustainable future. With a little practice, patience, and this ultimate guide by your side, you’ll soon master the art of composting, turning “waste” into “black gold” and becoming a true composting pro in no time!
Happy composting, and enjoy the incredible benefits it brings to your garden and the planet!