Is my compost ready to harvest? How do I set up my Biostack? Compost happens, but questions or problems may still arise. Following are some of the most frequently asked questions on the Compost Information Hotline. If you don’t find an answer, or need more help, give the Compost Information Hotline a call at 510-444-SOIL.
Ordering your Bin FAQs
- What is the difference between a backyard compost bin and a worm bin?
- Which type of bin should I buy?
- Where can I buy worms?
- Why Compost?
- I want to get a compost bin but know little about composting. Where can I learn more?
- Do other Counties sell compost bins?
- How can I buy a discount compost bin?
1. What is the difference between a backyard compost bin and a worm bin?
To start, the basic difference is what you put in your bin. A backyard bin is for composting plant trimmings, or plant trimmings combined with fruit and vegetable trimmings. A worm bin is designed for composting fruit and vegetable trimmings.
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2. Which type of bin should I buy?
It is important to think about what you want to compost (Garden waste? Fruit trimmings? Both?) and how much time you want to spend. A backyard or basic compost binis designed to compost plant waste alone or plant waste along with fruit and vegetable trimmings. A worm bin is designed for composting just fruit and vegetable trimmings.
For more information about compost methods, check the Choosing a System page.
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3. Where can I buy worms?
See our "Worm Sources" page.
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4. Why Compost?
Not only is compost great for plants and soil, it really reduces your waste, and our mission is to help Alameda County residents and businesses meet state and county mandates for waste reduction. Alameda County has a goal of reducing waste by 75% by 2010.
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5. I want to get a compost bin but know little about composting. Where can I learn more?
The Bay-Friendly Gardening Workshop Series offers free, hands-on workshops on many different aspects of Bay Friendly Gardening, including composting.
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6. Do other counties sell compost bins?
If you live in another county, contact the program for your respective county for more information. Some other discount compost bin programs are listed here.
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Maintaining your Compost Pile page/questions
Backyard Composting
- Where should I put my bin?
- My bin smells and is attracting fruit flies.
- I have ants in my bin.
- Can I put meat and dairy products in my bin? Why does my curbside program say I can put meat and dairy in my food collection bin?
- Should I put my bin in the sun so it can heat up?
- Can I compost weeds?
- My pile isn’t heating up, what should I do?
- Can I add pet waste to my bin?
- If I am adding material to my pile, when and how can I harvest?
- How can I tell when the compost is done?
- What should I do with the finished compost?
Backyard Composting
1. Where should I put my bin?
It is best to put your backyard bin directly on the soil and out of the direct sun. Placing on the soil (instead of concrete) allows decomposers easy access to the pile. Direct sun can dry out a pile and require more careful monitoring of the moisture. Over time the sun can also damage the integrity of a plastic bin.
A worm bin can be placed indoors or outdoors. Outdoors a worm bin should be located out of the direct sun. The hot rays of the sun can heat up a worm bin and kill the worms. During winter, it is important to provide protection from rain or frost. Worm bins are often placed in garages, under decks or basements.
Most important is to place your bin in a convenient location that allows for easy access and use.
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2. My bin smells and is attracting fruit flies.
The most common cause for odor and fruit flies is exposed food waste. Make certain that all food waste is covered. When adding fruit and vegetable trimmings to your pile, dig a hole in the center of the pile and mix in your food waste. Then cover with a layer of brown material (dry leaves or straw for example). If you have a fly infestation cover with dry brown materials and refrain from adding more fruit and vegetable trimmings for 3 weeks.
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3. I have ants in my bin.
Check the moisture. Ants are not harmful to the compost process but can be discouraged from nesting by adding moisture and turning the pile.
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4. Can I put meat and dairy products in my bin? Why does my curbside program say I can put meat and dairy in my food collection bin?
No. Meat and dairy products should be avoided as they can attract vectors.
Meat and dairy products are organic, compostable materials—this, along with the monitoring that takes place at large-scale composting facilities, is why your curbside program collects all food waste, including meat and dairy.
If you are composting any food waste, be sure to use a rodent-resistant bin with a bottom and no openings greater than ¼ inch.
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5. Should I put my bin in the sun so it can heat up?
A pile heats up because of the activity of the decomposers, not because of the heat from the sun. It is best to place your bin out of direct sunlight so that the pile doesn’t dry out too quickly.
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6. Can I compost weeds? What about ivy or noxious weeds?
Yes, and no. If you are hot composting, the temperatures in the pile will kill weed seeds. If you are more of a laid back composter, it is best to avoid weeds that have gone to seed. In general, it is best to avoid noxious weeds in the compost pile and instead place them in your green waste cart.
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7. My pile isn’t heating up, what should I do?
You may have too much brown, carbon-rich material. Try adding more greens—nitrogen rich materials, such as food waste or fresh grass clippings.
Check the moisture of your pile, it may be too dry. Add water until the pile is slightly damp and turn.
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8. Can I add pet waste to my bin?
No. Pet waste should be avoided as it can carry harmful organisms.
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9. If I am adding material to my pile, when and how can I harvest?
If you only have room for one bin, harvest finished compost from the bottom of the pile and keep layering fresh material on top of the pile. The Home Composter has a door at the bottom for easy harvesting. With other bins, use a pitchfork to scoop out the actively composting material into a pile until you reach the finished compost. Fork out the finished compost into a wheel barrow. Return the active pile into your bin. This can be a bit of work, but it’s a great way to turn your pile while reaping the benefit of finished compost.
Another method for one bin is to stop feeding it for a month and then harvest the bulk of the compost returning large uncomposted bits back into the pile for further composting.
The ideal is to set up two bins. Use one for active composting, the bin which you are currently adding material, and when that bin is full begin using the second bin. The first bin should have time to finish composting before the second is full. Harvest from the first bin before beginning the cycle again.
A 3-bin system is a great bin for ongoing composting. For more information, including building instructions, check the Building a Bin page.
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10. How can I tell when the compost is done?
Finished compost should be dark and crumbly with a sweet earthy smell. Generally, you shouldn’t be able to identify the original materials you added to the pile—those broccoli stems and leafy greens should have "disappeared", although egg shells and woody materials can persist. You can use a wire mesh screen to sift the compost and return the larger pieces back to your compost pile.
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11. What should I do with the finished compost?
Your own homegrown compost is a slow-release fertilizer, but when you distribute it in your garden, you are amending the soil—and, ultimately, increasing its nutrient content and its nutrient-holding and nutrient-cycling capacity.
Dig compost in. If you are creating a new bed, spread 2 to 4 inches of compost over the soil and then dig it into the top 6 to 12 inches of the bed. If you are putting in individual plants, dig a hole that is as deep as the rootball and 3 times wider than it. Rough up the sides of the hole. Mix 1 part compost with 2 to 3 parts soil to backfill the hole after putting the plant in.
Topdress freely. Spread fully decomposed compost around new and existing plantings. Put it under trees and shrubs and in garden beds, but leave 6 to 12 inches uncovered at the base of every plant. Use a layer no more than 2 inches thick, to ensure that air and water can easily pass through. Replenish every 6 months to a year, as needed.
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Worm Composting
- What kind of worms do I use? Where do I get these worms?
- How much food should I put in my worm bin?
- I have ants in my bin, what should I do?
- I have sowbugs in my bin, is that bad?
- What are the segmented white things in my bin?
- How do I harvest the worm castings (finished worm compost)?
- How do I use the worm castings?
Worm Composting
1. What kind of worms do I use? Where do I get these worms?
Compost worms are called "red worms" or "red wigglers". Their scientific name is Eisenia fetida. They are different from earthworms and nightcrawlers, which live underground. You can find red wigglers in an old compost pile, get them from a friend’s worm bin, or by them from a worm farm. Call the Compost Information Hotline at 510-444-SOIL for a current list of sources. Start with one half to one pound of worms, or two nice big handfuls.
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2. How much food should I put in my worm bin?
When starting a new bin, give your worms about a quart (one pound) of fruit and vegetable trimmings, then leave them alone for a couple of weeks while they get used to their new home. After that, feed your worms about a quart of food scraps per square foot of surface area in your bin per week.
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3. I have ants in my bin, what should I do?
Be certain food is covered and there is at least a 4- to 6-inch layer of bedding.
You can also try a light dusting of boric acid powder around the legs of the bin, spreading a light path of Vaseline or Vick's Vapor-Rub around the legs, using ant barriers around the legs, or setting the legs in small cans (tuna, cat food) with water in them.
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4. I have sowbugs in my bin, is that bad?
Don’t worry, these are good for your worm compost.
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5. What are the segmented white things in my bin?
They are soldier flies. You may also see them in your backyard compost bin. They hatch into slow flying black flies eventually and are harmless, as the larva help with the decomposition process.
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6. How do I harvest the worm castings (finished worm compost)?
You can start harvesting worm compost 2 to 3 months after you set up your bin. Simply reach in and scoop out the brown crumbly compost, worms and all. You can also move the contents of the bin to one side, place fresh bedding and a handful of soil in the empty space and bury food there for a month or two. Harvest the compost after the worms have migrated to the new food and bedding. To keep your worms healthy, harvest at least once a year.
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7. How do I use the worm compost?
Worm castings are one of the best fertilizers around. Sprinkle a ½-inch to 1-inch layer of worm compost at the base of indoor or outdoor plants, or blend no more than 20 percent worm compost into potting mix or garden soil.
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