General Composting Questions
What are the benefits of composting for the society as a whole?
Two main benefits of composting for society are reduction of waste and improvement of soil. Composting cuts down on waste and the intensification of landfills because it takes matter that society considers "waste" and reuses it in a beneficial way. Fewer things are going to the landfill. Benefits can be seen in agriculture through the application of compost as well. Compost adds needed nutrients into the soil that are removed by plants while they are growing. If these nutrients are not returned to the soil, then the soil gets worse and worse, and the crop quality declines over time. With the addition of compost, this doesn't happen.
How does Project Compost differ from other composting organizations?
Compared to commercial composting programs, Project Compost is very small. Jepson Prairie Organics, for example, is a composting facility based in Dixon. They process more than 7000 tons of compost every month, whereas Project Compost only does about 25 tons a month.
What can compost be used for?
Compost can be mixed in with soil to add nutrients, it can be applied as a "compost tea" to beds to add nutrients, and it can be applied in the form of compost tea as a foliar feed on leaves of plants to combat disease.
What is happening when you layer food and hay and why is it important for the piles to be dry?
Layering food and straw provides the necessary balance of nitrogen and carbon for a good fertilizer. Food scraps are rich in nitrogen, and hay is rich in carbon. These are nutrients that plants need to grow, and composting breaks them down into a form usable by plants. The piles shouldn' t be compleyely dry, but shouldn't be soaking wet either. The micoorganism that break down organic matter into compost need some water to live, but if there is too much water, they won't have enough oxygen (which they need because they are aerobic), and anaerobic microorganisms will take over.
What are some environmental risks of not composting?
More pollution, decline of soil quality, increased landfills. . .
Can I compost MEAT or DAIRY products?
These are organic materials and therefore can be composted, BUT they tend to smell and to attract more rodents and other critters. Decomposing meat may contain bacteria that's pathogenic to humans, so it has to be composted at a very high temperature to kill off the pathogens. Depending on the conditions of your pile, it might not get hot enough for that. So we discourage the composting of meat and dairy in backyard piles.
Can I compost DOG or CAT POO?
Because cats and dogs are carnivorous, the same applies here as composting meat and dairy products. Basically, they will attract rodents and may harbor pathogenic organisms. Dog feces may contain roundworm, and cat feces may carry the serious parasitic disease toxoplasmosis. These can both be passed to humans, so it's better to keep dog and cat feces out of the pile.
Can I compost OTHER PET FECES?
Feces from vegetarian animals like rabbits is fine! But if the animal is carnivorous (see above), then it's better to refrain.
Can I put WEEDS in the pile?
For most weeds, if they're green and haven't made mature seeds yet, then YES. But if they already have seeds, you may want to reconsider. A very hot pile over 140 degrees F can kill the weed seeds, but the entire pile might not reach that temperature uniformly. And a slow, unturned pile definitely won't be hot enough to kill them.
For weeds like Bermuda Grass or Morning Glory that reproduce vegetatively (i.e. not from seeds, but just break off a piece and it grows new roots), you should keep them out of your pile. But you can SHEET MULCH, which means you cover them with a thick layer (like 2 feet!) of cardboard/plastic and then straw or wood chips or other mulch, so that nothing can grow out into the light. Gradually they'll die and decompose under there.
Will too much CITRUS make my pile too acidic?
Some people caution against this, but it doesn't seem to be a problem. Citrus peels may break down slowly, but that's fine. Don't worry about the compost being too acidic finished compost tends to have a neutral pH, and our soils in Davis are on the alkaline side anyway so it's not a big deal.
Can I compost BRANCHES and TWIGS?
You can, but they'll take way, way longer to decompose than anything else. (Woody material contains a lot of lignin, which is a complex molecule that resists decomposition.) It's better to use braches and twigs for other uses in your garden, like making little fences or borders, or you can use it for firewood, get creative! Small young twigs are fine in the pile, but just be aware that they'll take a while to break down. You may want to have two piles, a fast one, and a slow one with twigs.
Can I compost food with PESTICIDES or plant matter with HERBICIDE residues?
Pesticides and herbicides will eventually break down, but some are persistent for quite a while before decomposing. They can also leach out of the pile and contaminate groundwater, so it's best to not use them in the first place! But if you do have small amounts in your pile, just make sure you get high temperatures and let it compost for at least a year before applying to soil. There are differing opinions on this matter, but we recommend trying to avoid having those chemicals in your pile.
Is the INK on newspaper harmful to compost?
Years ago, inks contained lots petroleum products, lead and other heavy metals. But now they're vegetable oil based, often made of soy oil. There still may be trace amounts of petroleum products and metals like zinc, but these are very very tiny, and they will be no problem in the soil. (If you live in an urban or suburban area, your soil is way more contaminated by other sources like pavement runoff anyway.) So ordinary ink, like colored or black/white newsprint, is COMPLTELY FINE. The inks to AVOID are glossy or shiny ones, like magazine pages. They contain more toxins, which could harm your soil.
Should I put DIRT in the pile?
It's not necessary to add dirt to a compost pile. Some people cover the pile with a layer of dirt to deal with fly problems. Dirt won't hurt your pile, but it's not a required component either.
Can I add ASHES to my compost pile?
Ashes are a good source of potassium for the soil, and it's fine to use moderate amounts in your compost pile. (About two buckets of a ashes for a 3 x 3 x 3 pile are fine. You don�t want too much, because they're very alkaline and can upset the pH of the pile.) DO NOT use coal ashes, because they contain large amounts of sulfur and iron that can injure plants. DO NOT use ashes from treated or painted wood.
Can you really compost HUMAN FECES?
YES! In China, farmers have used human feces as soil fertilizer for centuries. When composted correctly at high temperatures to kill pathogens, human feces can turn into a loose, crumbly, earthy-smelling, and completely safe soil amendment. This is a huge resource that our society is ignoring. To learn more about composting your own feces, read the Humanure Handbook by Joseph Jenkins! It's available free on online at www.weblife.org/humanure/
Is it okay to use BLACK WALNUT LEAVES?
Black walnuts produce a substance called juglone, which is toxic to other plants and inhibits their growth. Juglone breaks down in hot compost, but since the entire pile might not get uniformly hot, there could possibly be juglone in the finished compost. It's controversial to use black walnut leaves, and there are various arguments out there. So to be on the safe side, you can make a SEPARATE pile for them (see the eucalyptus question below), or send them to a large-scale municipal composting facility with higher temperatures than typically achieved in a backyard pile. The "green waste" from Davis is currently
Is it okay to use EUCALYPTUS or OLEANDER leaves?
Eucalyptus and oleanders contain toxins that inhibit the growth of other plants, but these are broken down by the composting process. Studies from the University of Arizona Plant Science Department showed that finished compost from eucalyptus and oleander contained no harmful toxins at all. However, if you compost these it's important to get the pile really HOT (by making it large, with lots of carbon, and turning often). To be on the safe side, you may want to make a SEPARATE pile with eucalyptus/oleander, and see how it turns out. To do a test, you can try sprouting seeds in tea from the finished compost, and see if they germinate.
Is it okay to use OAK LEAVES?
Oak leaves are tough and break down very slowly (it can take a couple years!). So if you want finished compost quickly, you may want to make a separate "slow" pile with oak leaves.
Is it necessary to use a compost ACTIVATOR?
No, it is not necessary at all! The microorganisms are already there in the food, the plants, the soil. They are everywhere, and we don't need to add them to the pile. But if you do want an activator to really get things going, here are a some natural and free ones: human urine, nettles, and finished compost.
Can I add SAWDUST to a compost pile?
It's fine to add sawdust, but not from treated wood. Because sawdust is very high in carbon, you should balance it with lots of nitrogen-containing materials like food scraps and fresh plant material.
Can I add PINE NEEDLES to a compost pile?
Pine needles have a waxy coating and break down very slowly. The are fine to put in your pile, but expect it to take a very long time. If you want an alternative, remember that pine needles are a great mulch for strawberry plants!
What about DISEASED PLANTS?
If your plants are diseased, the diseases may survive in the pile and then go back to your garden in the finished compost. So it's better to send them to a large-scale municipal composting facility, which reaches higher temperatures than backyard piles typically do, and will therefore kill the disease organisms.
Do I have to TURN the pile?
Nope! The pile will break down slower if you don't turn, but that's fine. If you plan to have a slow pile, make sure to include lots of carbon for airflow. If the pile doesn't have enough oxygen, it could get anaerobic and start to smell. But as long as it's well-aerated and drained, there's no need to turn it! Slow composting is very low-maintenance.
I just throw everything into a corner of the yard and don�t do much else. Is that okay?
That's fine! Your compost will break down more slowly, but if you're not in a hurry that's great. As long as it isn't smelling or attracting flies/rodents.then there's no problem! There are many ways to compost, and it's good to just experiment and do whatever works for you.
Do I need to WATER the pile?
If there's no moisture, a pile will not break down. So DURING THE SUMMER it's a good idea to water the pile. You can put a bucket in your kitchen sink, use a biodegradable soap, and collect the dishwater for your compost pile! (You can also use your shower or bath water.)
HOW LONG will it take to get finished compost?
It depends. A pile of at least 3 x 3 x 3 ft. is insulated enough to get hot in the middle, so it will decompose much faster. If you have a good carbon to nitrogen ratio of 2:1, it will also be faster. Turning the pile accelerates it (due to improved aeration), so your compost will go faster if you turn often. Chopping the material up into small pieces also speeds up the pile, by increasing the surface area for decomposition. At minimum, you can get finished compost in just a few weeks, about one month. But it's also fine to have a slow pile, if you're in no hurry! If you never turn the pile, it could decompose slowly over a couple years. The end product will be just as good, either way.
How will I know when the compost is FINISHED?
-It will look like uniform, loose, crumbly dark earth. -The pile cools down and will not heat up anymore, even if you turn it. (Sometimes a pile cools but then heats up when you turn it, meaning it�s not done yet.)
How long will my pile take to produce finished compost?
Compost can happen quickly, or can be a slower process. If the ingredients are finely chopped, and proper conditions are present, finished compost can be produced in as little as 14 days. A pile in one's backyard may take six weeks or so. The piles that Project Compost maintains take almost three months to be fully done.
My compost pile smells. What do I do?
It may be anaerobic, meaning there's not enough oxygen. (The bacteria that live in the presence of oxygen don't smell, but the ones that live without oxygen produce smelly gas as they digest.) So you may need to improve the airflow in your pile, by adding more carbon materials like straw or dry leaves. Turn the pile, and keep a nice thick layer of carbon on the top.
You may have too much nitrogen (fresh wet) material, and not enough carbon (dry brown) material. If there's excess nitrogen it turns to ammonia, which smells. So add more carbon!
My compost pile isn't breaking down? What do I do?
The pile may be too dry or not be getting enough nitrogen. Try watering the pile so it has the moisture of a wrung out sponge. Also try adding nitrogen, such as coffee grounds, manure, grass clippings, or food scraps. Try turning the pile to aerate it.
My compost pile has flies/rats/other critters. What do I do?
Your pile may have exposed food matter. Keeping your pile well covered with a thick carbon source like straw helps, but the only way to absolutely prevent critters is to have a critter-proof bin. A completely enclosed commercial or home-made bin (with small openings for aeration of course) may do the trick, or you can use a compost tumbler. Tumblers are completely rodent-proof because they're raised off the ground on legs. With lots of carbon and good aeration, flies shouldn't be a big problem. Frequent turning of the pile also helps to control flies. With lots of carbon and good aeration, flies shouldn�t be a big problem. Frequent turning of the pile also helps to control flies.
Where can I get carbon for my pile?
Lots and lots of places! Good sources of carbon are almost any dry thing. Pay attention in fall to when leaves drop off trees and collect lots of them to use throughout the year. Project compost uses used animal bedding from animal barns of the U.C. Davis campus. Straw, leaves and dry grasses are all good. Many businesses throw away shredded paper, and this is a good source of carbon as well.
My worm bin is full of little critters that ain't worms? Whats up?
There are many critters in your bin, besides just worms and that's fine! The bin is a functioning ecosystem with prey and predators, primary and secondary consumers. The only unwanted creatures are those that harm the worms or are unpleasant to humans (e.g. ants, fruitflies, centipedes). But most bugs you'll find, like springtails and sow bugs, are no problem at all.
My worm bin smells. What do I do?
Probably feeding too much, so it's rotting anaerobically. Cut back on food until the worm population grows. Smell could also mean lack of air, increase bedding and ventilation!
My worm bin has flies. What do I do?
Either your food scraps have larvae from the storage container (store in fridge) or you don't have enough top bedding to cover the food (add more bedding, cover with cardboard).
My worm bin has ants. What do I do?
Raise the bin above a "moat" of water so they can't climb into it. Ants sometimes also mean the bedding is too dry.
My worm bin has earthworm mites. What do I do?
Remove the mite-infested food, and bait the mites by putting a piece of bread in the bin and removing when the mites congregate on it. Also reduce bedding moisture.
My worms are trying to escape. Why?
There may not be enough food, too hot in the bin, the humidity is too high, or toxic from too many castings! If the environment is comfortable, they won't leave.
Can I have my worm bin outside is super cold weather?
The worm bin should be insulated if it is outside in very cold, or freezing weather. Achieving a balance between insulation and aeration will be difficult, as a lot of insulation will be necessary. Another thing to consider is rain. The bin must be shielded from the rain, as water may get in the air holes and drown the worms. Straw and leaves are great insulators, but the air will still penetrate and may still be too cold for the worms, who like the weather to be maintained as we do. One way to keep the worm bin warmer is to keep it right next to a building, as the building retains heat.
Where can I get RED WORMS?
Red Worms can be found in aged compost piles that are cooling down, or you can purchase them from a worm farm. The two nearest worm farms to Davis are Sonoma Valley Worms (1-800-447-6996) and Easy Crawler Worm Farm (530-908-0744) in Dunnigan, Yolo County. Worms typically cost about $10 - 20 per pound. Don't get them from a bait store, as they are very expensive there! Project Compost is currently beginning its own worm farm, and hopes to provide worms to the community in the future.