What you can and cannot compost
Things you can compost!
| Materials | Carbon or Nitrogen | Details |
|---|---|---|
| Alfalfa meal and hay | Carbon | Shredding or chopping it up will help it break down quicker |
| Algae, seaweed and lake moss |
Nitrogen
|
Good source of nutrients and minerals. |
| Apple pomace (cider press waste) | Nitrogen | If dried use as a carbon |
| Ashes (wood, not coal) |
Neutral
|
Use only wood ashes since coal ashes can be toxic to plants. Use sparingly as a pest deterant. |
| Beverages, kitchen rinse water |
Neutral
|
Help keep the pile moist, but don’t over do it. |
| Buckwheat straw or hulls | Carbon | Shredding or chopping it up will help it break down quicker |
| Cardboard |
Carbon
|
If you have lots of this, consider recycling it. Otherwise, shred into small pieces in pile. |
| Cat litter (unused!) | Carbon | Ugh..make sure its unused |
| Clover | Nitrogen | Add it for a bit of luck! |
| Cocoa hulls | Carbon | Shredding or chopping it up will help it break down quicker |
| Coffee grounds (and filters) |
Nitrogen
|
Great source of nitrogen and worms love coffee grounds! The filter will break down so add it too! |
| Cornstalks, corn cobs | Carbon | A little tricky, so shred and/or break down and mix well into pile. |
| Cotton Bur | Nitrogen | Great to use to jump start your pile or warm it up |
| Cowpeas | Nitrogen | Add them if you got them! |
| Dog food |
Nitrogen
|
Best if not a meat based dog food |
| Dryer lint |
Carbon
|
Yum, lint. Make sure you moisten it a little before you add it. |
| Eelgrass | Nitrogen | If dry use as a carbon |
| Egg shells |
Neutral
|
These break down slowly, so make sure to crush these before adding. |
| Feathers |
Nitrogen
|
Slow to break down, shred if possible to speed up process |
| Flowers | Nitrogen | Green use as Nitrogen, dried use as carbon |
| Fruit peels (not limes) | Nitrogen | Best if you cut them up to small pieces |
| Grape pomace (winery waste) | Carbon | When dried and shredded best used as a carbon |
| Green Grass clippings |
Nitrogen
|
When green can be used as a Nitrogen |
| Dried Grass clippings |
Carbon
|
Make sure they are not too wet and mix with dry leaves for best results. |
| Hair |
Nitrogen
|
Good source of nitrogen. Make sure you scatter, so it doesn’t clump. |
| Hay |
Nitrogen
|
The best kind is hay that is not suitable for livestock and is starting to decay on its own. Make sure it is dry and weathered. |
| Hedge Clippings | Carbon | Shredding or chopping it up will help it break down quicker |
| Hops (brewery waste) | Carbon | When dried and shredded best used as a carbon |
| Kelp (seaweed) | Carbon | Good source of potassium (perfect for growing potatoes!). Use sparingly or sprinkle kelp meal in to get your pile cooking. |
| Leather (leather waste) |
Nitrogen
|
Shredding or chopping it up will help it break down quicker |
| Leaves |
Carbon
|
Shredding or chopping it up will help it break down quicker |
| Manure from herbivores (cow, horse, pig, sheep, chicken, rabbit) |
Nitrogen
|
Best if known to come from a herbivore |
| Newspaper |
Carbon
|
Shredding or chopping will help it break down quicker |
| Nut shells | Carbon | Shredding or chopping will help it break down quicker |
| Oak leaves |
Carbon
|
Shredding or chopping will help it break down quicker |
| Oat straw | Carbon | Shredding or chopping will help it break down quicker |
| Sawdust and wood shavings |
Carbon
|
Preferably not from kiln-dried wood |
| Paper | Carbon | Shredding will help it break down quicker |
| Peanut hulls | Carbon | Shredding or chopping will help it break down quicker |
| Peat moss | Carbon | Also great to add to your garden soil |
| Pine needles and cones |
Carbon
|
Shredding or chopping will help it break down quicker |
| Tea leaves | Carbon | Best if shredded to help it break down quicker |
| Vegetable peels and scraps | Nitrogen | Kitchen scraps are a great source of nitrogen |
| Vetch | Carbon | From the pea family, yup add it too |
| Weeds |
Carbon
|
Don’t add if your concerned about spreading the seeds |
| Wheat straw | Carbon | Best if shredded to help it break down quicker |
Things you should NOT compost!
|
Materials
|
Carbon or Nitrogen
|
Details |
|---|---|---|
| Ashes (coal or charcoal) |
n/a
|
May contain materials that are toxic to plants. |
| Cat droppings/litter |
n/a
|
These may contain disease organisms and should always be avoided for composting. |
| Colored paper | ||
| Dog droppings |
n/a
|
Same as cats. |
| Lime |
n/a
|
Acidity can kill composting action. |
| Meat, fat, grease, oils, bones |
n/a
|
Do not break down, can coat materials and “preserve” them, can attract pests. |
| Nonbiodegradable materials | ||
| Toxic materials |
Things that MAY be composted, but only with caution and skill
| Materials | C/N | Details |
|---|---|---|
| Bird droppings |
Nitrogen
|
Some bird droppings may contain disease or weed seeds |
| Diseased Plants |
Nitrogen
|
Make sure your pile gets to at least 135 degrees Fahrenheit for a few days to let it “therma kill” the disease |
| Milk, yogurt, cheese |
Neutral
|
May attract pests, so put it in the middle to deep into the pile |
| Weeds |
Nitrogen
|
For best results, dry them out until crunchy, then add them to your compost pile |
| Sod |
Nitrogen
|
Like diseased plants, make sure your pile gets hot enough to make sure the grass doesn’t keep growing in your pile. |
{ 162 comments… read them below or add one }
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What about moldy food? Can we add them to the compost?
@Lara, Yes, adding molding food is fine, it will not hurt adding it to your compost pile.
No dont add any cooked food unless you want to attract rats. Moldy bread for example is a no no!
What about rotten vinager? I have an old bottle of Spectrum organic white wine vinager and it grew “mothers.” BUt it smells too yucky to still eat. Hate to waste it. Can I compost it?
@Janeen, Yes, you can but I would not, it will likely smell and it might kill some of the beneficial organisms found in your compost pile. Pour it down the drain and it will likely clean your drain out a little.
Just repotted some plants and I have old roots and soil mixed in with lava rocks. Is it okay to add to the compost?
@Diane, Add the soil but get rid of the roots, they will break down but now knowing what type, they may spread when using your finished compost.
Can you compost cooked corn cobs, (the hard bit left after you eat all the kernals) Will it decompose??
@Jacob, Yes, you can add corn cobs but you will find they take a while to break down. If you can cut them up or shred them it will help speed up the process.
Why not Lime rinds(skin/peel)?
@J.Karl Lipscomb, Adding lime rinds is ok they are just acetic and take a while to break down. Try chopping them up or shredding them to speed up the process and do not add to may at a time unless you have a fair amount of browns.
Great website! I live on a lake. Can I compost lake weeds?
@Carol, Yes, lake weeds are fine to compost.
My dad doesn’t want to but when I’m a grown up I’ll follow each and every instruction shown
@Seth, Glad to hear you are looking forward to composting, it’s a great way to recycle and when done properly finished compost can be a great source of soil for your garden and plants.
Seth’s comment just fills my heart with Joy! I was the same at his age in a resistent house. You’re an inspiration Seth!
I was once told that the contents of your domestic vacuum cleaner (ie general household dust etc), can be composted.
is this true
@Dave, Yes you can, while hair may take a little longer to break down the content from your vacumm is perfect for your compost pile/bin.
When I added my vacuum contents, it looked like it killed some of my worms. Would you know why? It did directly touch some of the worms when I put it in.
@Andi, Not knowing what you are vacuuming its hard to know why. I would just avoid putting those in your worm bin. Typically I only add shredded newspaper, and finely chopped kitchen scraps to my worm bin.
I have a large barrel of raspberry puree…..can I work this into my garden soil?
@Kristie, I would not sugget it, it will likely attract rodents and bugs.
You need to reverse your answers to grass clippings and leaves on your what you can and cannot compost chart. Grass clippings are Nitrogen and Leaves are Carbon. You have it reversed. Thanks for all of the helpful information on the site. Very good resource.
@Norm Schwertfeger, Thanks Norm, the corrections were made!
My husband brews beer and we have a lot of grains that have been boiled from the process….I assume this should not go into the compost since it is essentially cooked?
@Rhonda, Yes, you can compost the barley from the beer making process. I suggest you let it dry out and use it as a carbon (brown).
Hey Steve I am starting a composting bin now. I bought a composter from home depot, it is the barrel kind, with a handle for turning.
Do these work? I just started it but feel I have difficulty with turning the compost and getting all in one pile.
Any suggestions?
@Lauren, I’m not familiar with that particular bin. See if you can take the handle and gear off once it’s too heavy to turn with it. Then use a rocking motion to turn it, use the momentum to give it the final turn.
Thank you for all the great information. Getting ready to start composting for the first time. I do a lot of juicing and smoothies, so I know my veggie/fruit scraps can go but what about cooked quinoa, pasta and beans. Will that attract unwanted critters? I’m still amazed at some of the things that make great compost!
@Donna, Yes it can attract critters so you want to make sure you use a quality bin, maybe a tumbling style so that its up off the ground. Also, make sure you have browns (carbon) as the majority of the mix (3 to 1). You may want to consider vermicomposting which is great for people how have excessive amounts of kitchen scrap.
I couldn’t find those on either list from several resources so thank you for the education. I am really excited about my new project.
Hi, is it recommended to compost cooked potatoes? Thanks
@Josh, Adding cooked potatoes to your compost bin is fine; just make sure you bury it as deep as you can so it does not attract critters.
It helped me with my homework.
THANKS!
I live in the Caribbean, so its hot year round. I’m starting to put things in a compost tumbler for the first time. After the first few days I opened it up to add things. The smell like ammonia was so strong! All i put so far was fruit peel and some peat moss. Did i do something wrong? I still don’t know where to place the tumbler. Is it going to leak out liquid from time to time? If I don’t add the flowers (the seeds) from then weeds that I’m pulling form my lawn, would that regenerate? Thanks for the tips on what can and can’t go in the composter.
@Lan, When your compost smells you are likely adding to much nitrogen, like kitchen scraps. Remember the ratio for adding material to your compost bin is 3 to 4 parts carbon to 1 part nitrogen by weight, so 3 to 4 pounds of leaves (browns) to every one pound of greens (nitrogen). This means the majority of your material being added should be browns. This would include leaves, shredded paper, dried grass, etc. Also, you want it as wet as a well rung out sponge. I advise adding more browns, giving it a good mix and see if the odor has dissipated.
We have numerous walnut trees which produce well. Can we compost the nuts they drop?
@Steven, Yes you can compost walnuts however the shells will take a while to break down, possibly a year or longer. The actual nut inside should break down in a more reasonable amount of time. Make sure you crush, chop or break both the shell and nut up as much as possible.
For clarity: I have the walnuts. I know I can compost the shells but what about the husks around the shells? (I’ll be keeping the actual nuts! =-)
@Leona, As far as I know, the husks around the shells is ok to compost, however you should do your best to cut them up or shred them.
i have a question, can you make compost in winter.
@davidpdesantis, Yes, you can compost during the winter, however it will slow down significantly and maybe stop completely if you live in a very cold climate. If you live in the south you will have better results compared to living in the north.
I have a homemade 55 gal drum that tumbles. It is getting pretty heavy. At what point should I stop adding more to it. Things seem to stay pretty damp in there. I have drilled air holes around it, but not sure how much air gets in. Any suggestions as to what to do with my kitchen scraps when I’m not adding them to my tumbler? Should I just start a pile on the ground? This is my first year to compost, and next spring will be my first big garden. I’m having a lot of fun preparing.
@Janet, Once your compost bin is full to the top or 3/4 full I would stop. Remember the material will settle so if you start with it full by the time it finishes it will be less than 1/4 full. Most people who compost find they need another composter so they can add new material while the other composter is finishing. Yes, you can just pile it on the ground but that may attract unwanted guests. As for venting, make sure the holes in the composter you have made are at least 1/2 inch in diameter, anything smaller will likely get clogged. Also, make sure you have drain holes in the bottom of the compost bin so water can drain out.
Thank you Steve, I was just researching why my compost (in tumbler) stays wet. I had previously bookmarked your site so this is where I started. I just read about the holes in bottom of tumbler to allow for drainage. I think that may be my problem. I have been adding more dry material, but it hasn’t quite made the difference I thought it would, so I think I will drill some holes in bottom to see what that does. Also, I am finding that the leaves aren’t breaking down very fast – certainly not as fast as the other materials – more nitrogen needed? Most of the leaves are from my pecan tree
@Donna, Try shredding, or cutting the leaves up with a lawn mower or chipper, this should help them break down much quicker.
Hi Steve,
Along the same lines as Janet’s question about what to do with extra kitchen scraps, I live in northern Minnesota and have plenty of freezer space to hold frozen fruit and vegetable scraps – if it’s ok to use them next spring for my composter. Does freezing negatively affect the enzymes and nutrients?
Great site – thanks for all the help!
@Larry, No, freezing fruit and vegetable scraps does not affect them in a negative way, I know of several people who freeze kitchen scraps to add at a later date.
Can canned pinto and kidney beans be composted? Also, on the October 15th it says you can compost walnut shells. I’ve heard that you should not ever use walnut leaves or sawdust except to prevent plant growth. A friend told this is why he uses walnut sawdust for his trail mulch. Have you heard anything about walnut sawdust or leaves?
Thanks,
Rob
@Rob, Yes, canned fruit and veggies can be composted. The walnut question was in regards to the shells not the leaves, and as far as I know the shells are fine to compost as well as sawdust.
I live in the northeast USA. Can I compost directing into my garden over the winter months? I don’t an established compost pile yet and I hate to waste the dried leaves I have collected and all the vegetable scraps and coffee grounds from the kitchen all winter.
@Gretchen, Composting in the northeast during the winter can be tough, but there is no reason why you can’t. The pile may just freeze when it gets really cold, so you may want to cover it with a tarp. When the weather begins to change and it warms up turn the pile and keep it moist and it will reactivate and take off where is left off.
Is it better to pull dead plants up and put in a compost heap or leave them to decompose in the garden for next year?
Also, do you need a closed bin for compost or are open frames okay?
@judy, Not sure if there is a better way, it’s likely that they will break down quicker in a compost bin. Remember, just about everything breaks down and all you’re doing in a compost bin is creating the most ideal conditions for organic matter to break down quicker. If you leave the plants in the planter or garden they will break down quicker if you chop them up or use a tiller on them.
Sorry to beat a dead horse and no I don’t seek to compost one either. However, about walnuts… I’m reading “yes” to nuts and shells and “no” to leaves. But what about the husks around the shells?
Great site, you’ve given me many great idea’s!
@Compost Noob, As far as I know composting the husks around the walnut shell is ok. Make sure you cut them up or shred them so they break down faster.
Hi, I’m a bit confused about whether weeds are nitrogen or carbon? In the first table they are listed as carbon, then in the last table they are listed as nitrogen. Which is it?
@Elizabeth, Sorry for the confusion, fresh weeds should count as nitrogen, dried weeds are carbon. Make sure there are not seeds with the weeds, unless your compost gets to 140 degrees the seeds will be passed on.
Can you compost outdoor potted plants that have died from the frost/cold? These are hanging potted impatiens, marigolds, petunias, etc. There is vermiculite in the potting soil. Would I be able to use the entire contents of the flower pots?
@Kikatti, Yes, you can compost impatiens, marigolds, petunias, etc, that have died, try to chop them up or shred them. The vermiculite will not break down for some time but it will not harm anything.
What about Redwood leaves and Camellia leaves and flowers?
@Diane, Redwood leaves, Camellia leaves and flowers will all compost well, just make sure you grind or shred them thoroughly.
would corn meant for cattle feed provide nitrogen? u only mentioned corn plant remnants not actual corn.
@J, Yes, fresh corn would be considered a source of nitrogen for your compost bin.
Can you use onion skin and egg shells in your compost
@Jackie, Yes, you can compost both egg shells and onion skins. Keep in mind the egg shells should be crushed up and will still take longer to break down and the onion skins may smell. If you bury then deep within the pile it will help with the smell.
How about the leaves from a tree of heaven? There’s alot of it, but I’ve been told it’s not good for compost. I’d like a 2nd opinion.
@Joe, The reason some think composting the “tree of heaven” leaves is a bad idea is because it seeds prolifically. You do run the risk of collecting some of those seeds in the compost and therefore spreading them when you spread the compost. It’s a fair risk but you could just pull the seedlings out when they begin to sprout around your yard, the risk and extra work is your choice.
Hi Steve,
I have a big block and the neglected back corner has a huge problem with rhizomatous golden bamboo, a noxious weed where I am (Australia). I’ve been taught the best way to get rid of it, but I’ll be left with hundreds of 6-10 foot stalks. Can I compost them green after shredding, or should I dry then shred them for use as a carbon (Or, indeed, should i get them as far away from my property as possible to prevent regeneration?)?
Thanks,
Allan
@Allan, Some would say shredding is enough, but if they are that much of a problem, I would remove them as far away as possible, no need risking it.
I have a huge Eucalyptus Tree, is it okay to use theses leaves there are SO many? someone told me not to?
@Diane M. Eucalyptus leaves can be toxic to other plants, this is the reason it’s not recommended. If you are using the compost to build up the soil in an area where you will not be planting anything then it would be ok, otherwise it’s not recommended.
Can you compost the following items: old pizza boxes, used napkins, old leftover dinners (rice, sauces, etc), sweet stuff leftovers (cupcakes, muffins). Any help would be great! Thanks!
@homesteaders
Yes, you can compost all of that stuff in limited amounts. But here’s the issue. Food-like items should be buried deep in the pile to avoid attracting rodents or pests. And cardboard can also only be composted in limited amounts, because it is extremely dry and carbon rich and can slow down your composting if you have too much. If you have a very big compost pile with a lot of other stuff in it, then it probably won’t be a big deal. If that stuff makes up 20 percent or more of your compost, then it’s too much and will probably end up either stinking, slowing down your compost, attracting pests, or all of the above.
can you compost dog hair
@mary cummings, Yes, you can compost dog hair. Like human hair or most any hair, it will likely take a little longer to break down but it will eventually.
I live in Northern Illinois where it gets cold in the winter. I am looking to purchase a dual chamber tumbler and would like to start my composting now (I do know that it slows in the winter). Could I use shredded newspaper instead of leaves? I do not have garbage service and have always had a compost pile that was not enclosed. I now have moved and have a raccoon problem so I need to get an enclosed composter. I also have an excess of newspapers. Also, I am looking to buy the forest city tumbler at or two ecomposters. Are you familiar with these? Is one better than the other? Thanks, Leslie
@Leslie, Yes, both composters are ok, however the forest city tumbler is not suitable to use as a dual chamber composter due to its size, it works better as a single chamber composter. The ecomposter is not as functional as a traditional tumbler like the Spin Bin however it does work. There is no such thing as a perfect composter it’s a matter of what works best for you. I find the tumblers work best for me since I am a lazy composter and like the fact that I can tumble them once or twice a week and the material is broken down in 8 to 12 weeks.
Hi – I’ve always composted meats and fats. They sure do breakdown! Otherwise the world would be covered in them!
If you have vermin like rats in your neighborhood, they will go after any food. As will racoons, opossums, etc.
But I’ve never had rat problems in city, suburb, or rural areas when composting these items.
I often dig a hole in my compost pile and place the meat/carcass in there. Never have I had it disturbed and it’s soon decomposed into unrecognizable parts.
@Bill, Yes, there is no doubt you can compost these items however you are unique that you have not attracted other animals to your compost pile. Many times this is the problem with using such methods and why we do not recommend.
Hello,
Acidity is not good for compost….so can I put orange or lemon in my compost bin?
@Ginny, Yes, you can put small amounts of orange or lemon in your compost bin, just not more than one ot two. Be sure to cut them up as much as possible.
Hi,
Thanks for the great advice! I have just got a compost bin and am looking forward to using it. Should I choose a sunny or shady spot in the garden?
I have also heard that burying the bottom of a compost bin keeps the rodents out – is this a good idea or does it just trap the liquid?
A friend suggested a contraption that has a twisty end to “stir up” and aerate the compost to prevent having to turf the material out and mixing, do these work?
Thank you for all the advice in the above replies, I have read them all and feel much more equipped to start my composting.
@Amber, The best spot for your compost bin is a sunny spot, especially in the winter. Yes, you can bury the bottom of the compost bin into some dirt, but if the rodents really want in, they will dig or chew through. Try to bury the food scraps deep within the compost, this will help. I think the best way to mix your compost bin is to lift it off the material and then using a fork or shovel and it back to the bin. Of course if you bury the bottom of the compost bin in dirt this is not too practical. Those mixing tools have not worked well for me. Another option is buying a tumbling style composter, all you do is add the material and give it a turn every few days.
I keep hearing that bread products and citrus peels are not good for composting. That doesn’t seem to be the case here. Why would people put these items on the “not list” and what is your opinion?
@laurie
Bread and citrus are fine, in my opinion. Here are the potential issues. Bread can attract pests like rodents if you have a lot of it, so you’ll want to bury it deep into the compost bin or pile. Citrus rinds can sometimes be a little slow to break down. Some people say that they are “too acidic,” and will affect the pH of the compost, but I don’t consider that to be a valid issue.
In general, everything organic breaks down! You don’t have to worry too much.
Hi there! This is such a great website. Thank you so much for all of your time and important information.
So, I started my composting bin this summer, being told to basically layer one of brown to one of green. Now I’m worried I’m going to have serious nitrogen burn! Is it too late to add in a lot of carbon – leaves, dried grass, etc? Once the snow and ice melts (in the NE) and we have a day of sun, everything will go back to dry and crunchy, so it’s possible.
Also…I didn’t start with worms, but would really like to as it’s a quicker process. Is there any way to do this with the current bin (about 3/4 full) or should I start a new one when it warms up? Thanks!
@LC, Layering your compost is a good way to start, but keep in mind, the layers are temporarily. After a week or less you should start aerating the compost, in other words you need to mix it regularly. If possible, lift the bin off the compost set it next to the pile and add it back to the bin, this is a quick way to mix it. Yes, you can add more material; the ratio should be roughly 1 part nitrogen to 3 parts carbon by weight. This type of bin is not a worm bin, you may have some worms work their way up from the ground but actual vermicomposting requires a bin to collect the liquids and trays that hold the worms, their castings, and food.
Hi Steve
I have been composting for a while now and we have a lemon tree and have way more lemons than we can ever consume, and possibly more than our compost bin can consume. We have also been putting meat without bones into the compost.
I figured that if maggots can be inside a compost bin, and they’re a protein, then surely meat can too?
Also, what is the best way to compost lemons?
When aerating the compost it smells very very citrus…to a point that it is putrid. I’d also say the meat contents adds to the putrid smell but does this really affect the ability of the micro-organisms to decompose the material or is it just the perception that the oils inside the meats may slow the process down?
Can’t wait to here from you, thanks.
rgds
Ryan
@Ryan, Yeah, you need to cut back on the lemons, do you have some neighbors who could use them. Also, good job composting meat, we don’t recommend it but if you can get your compost hot enough then maybe it works for you. If you keep up with the lemon and meat you will continue to have stinky compost. If done right, i.e., limited citrus and no meat, your compost will have little to no odor.
Hi, am in the process of making a compost bin, is it possible to make it with 4 pallets or do they have too many holes? Does it need to be closed?
@CJ, Using pallets to make a compost bin is a great idea and works well. You may need to use chicken wire in the inside to help keep the material from falling between the slats. Buy a heavy gauge so your shovel or pitch fork does not tear it up when mixing.
I have just purchased a compost bin here in Queensland, Australia & enjoyed reading this site. I can now educate my husband on the do’s & don’ts, as I continue to research more on the subject. We already have red worms where I have placed the bin.
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