How To Compost

nature's way Composting is just Nature’s way of recycling. By definition, composting is the controlled decomposition of organic material such as leaves, twigs, grass clippings, and vegetable food waste. Compost is the valuable soil product that results from proper composting. Composting helps to keep the high volume of organic material out of our landfills and turns that material into a useful product. With organics making up a significant part of California’s municipal waste, onsite composting reduces the cost of hauling garbage and operating landfills. Compost is great for gardens and landscaping, and you can save money by buying less soil conditioner, mulch, and fertilizer.

Composted material is actually rather expensive to buy. Anyone with a little extra room in a garden, a little extra time, and a good source of compostable materials can produce good, high quality compost in as little as 6 weeks. When you compost, you return the earth's nutrients back to the soil, where your plants absorb them and grow healthy and strong. Healthy plants are far more resistant to diseases and pests. Instead of throwing away your organic waste, compost them! Be a part of prolonging the life of Riverside County's landfill space by composting at home.

It is a satisfying way to turn fruit, vegetable and yard trimmings into a dark, crumbly, sweet smelling soil conditioner. Composting is fun, easy, and educational.

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Selecting a Good Spot for Composting

Composting can be done in the sun or shade in Riverside County. Pick a spot that is convenient to the kitchen or garden and close to a source of water. Keep the pile away from structures and wood because the material will be moist and could hasten decay in a structure. Always place the compost pile on bare ground. Essential organisms from the soil are needed to breakdown the material. Plus, water used to moisten the pile will need to runoff and needs a place to leach into the soil.

Composting Ingredients

When composting, we are just accelerating the natural decomposition of plant material. By controlling the environment of the compost pile you can determine how fast or slow you complete the compost process. There are four basic ingredients in the compost pile: nitrogen, carbon, water, and air.

Nitrogen - Green materials such as grass clippings, fresh leaves and twigs, vegetable and fruit trimmings, coffee grounds and filters, and non-meat eating animal manures (chicken, rabit, horse, sheep or goat).  Most any plant material that has moisture or "life" still in it is considered a green material.

Carbon - Brown materials that have released their nitrogen are usually dry and brittle.  Dry leaves and grasses, straw, wood chips, corn stalks, shredded newspaper, paper towels, napkins, and cardboard are all good carbon rich examples.

Water - Adding water to the pile will balance the correct moisture level.  The proper moisture should be about the same as a damp wrung out sponge.  Few drops should fall when the material is squeezed in your hand.

Air - Oxygen is very important to the organisms that are working in the pile to break down the organic material.  Bacteria, fungi, microorganisms, and insects need oxygen to breathe and air space in which to move througout the pile. 

Avoid These Items

There are ingredients that you will want to avoid in the compost pile. They can create odors or attract unwanted pests, or have pathogens that won’t be broken down by the heat of a compost pile.

Don’t put any meat, dairy products, fats, or oils into the compost pile. These materials tend to putrefy instead of breaking down, and will attract a wide variety of pests, including flies, rats, raccoons, stray dogs and cats, etc.

Don’t put dog and cat wastes into the compost pile. The fecal material from any animal that eats meat contains several pathogens which will survive the compost process.

Don’t put thorny plant material in the compost pile. The thorns might not break down completely and you could get stuck when you are digging in the garden or compost pile with your hands.

Don’t add diseased plant material in the pile. The disease may not be killed by the heat of the pile and transfer to other plants when you use the finished compost in the garden.

Methods of Composting

Aerobic Composting

Aerobic Composting in a Bin or Pile is simple and effective. The key to this method is the size of the pile. You’ll want a heap about 3’x3’x3’ or one square yard. This gives you a volume of material that creates the proper environment for maximum production in the pile. If the pile is too small, the material won’t breakdown. If the pile is too large, it will be difficult to manage and it will be slow to compost.

Assemble the pile using green and brown material. Start with equal parts, an easy way to mix and measure at the same time is to layer the organics in 1" to 2" alternating layers adding water in between. After assembling, water well and cover the pile with a tarp, carpet, or an opaque plastic sheet. This will help hold heat and moisture. If you have selected to use a compost bin, you will need to build these layers in the bin.

Keep adding materials to the pile, it can be a slow process. Most composters don’t have enough material available at one time so might take a few weeks to gather the materials together. The center of the pile will reach temperatures of 120 to 160 degrees when the micro organisms are working. These temperatures do the ‘cooking’ to kill bacteria that are harmful and prevent the germination of seeds when the compost is used. The temperature will stay up as long as there is material to be broken down and you are actively mixing the material. You will notice that the pile is hot for a few days; then it will begin to cool. This means it is time to turn and mix the pile to add oxygen and water if needed.

Turn the pile weekly. Frequent turning will help speed-up the break-down of the material. Continue composting until the pile has a dark rich look like chocolate cake and the things you put in don’t look like their original form.

Completing the compost process.  After it appears that the compost is done, water well, cover, and let it rest for one to two weeks to make sure it is completely done and the nitrogen has a chance to stabilize. If the compost is used too soon it could rob nutrients from the surrounding plants. After resting, it is ready to sift through a ½" hardware cloth strainer to remove the large chunks or simply rake through and pick out the big pieces that need more time to break down (use these in the next pile for a quick start because they already have the bacteria and fungi on them). Larvae, insects, and grubs should also be removed before you incorporate the compost into your soil.

Start to finish, you can have completed compost in 6 weeks to 2 years. It all depends on the material, method, and the effort you put into it. The more actively you maintain the pile the faster you will receive your reward.

Anaerobic Composting

Anaerobic composting in a bin or pile is using the same materials as above, but you are not actively turning and mixing the materials. It is slower to make compost and could take a year or two. Since the pile doesn’t heat-up, seeds would not be killed. It’s real easy, just pile the stuff, water, cover, and wait. The compost is still beneficial to your soil and you will have kept it out of the landfill.


Vermicomposting or Vermiculture

see our Vermicomposting page.

Using Compost

Not only does compost help the environment, but it can help your garden, yard, and house plants too. After about 6 weeks or when compost looks like soil and smells sweet and earthy, it is ready to use. Here are some of the most common ways to use compost.

In the Garden - Before planting, mix a 4" to 8" layer of compost into newly reclaimed or poor soils. Dig the compost into the top 6” to 12” inches of soil. Mix a 1/2" to 3" layer of compost into annual garden beds at least once a year. Compost will add nutrients and beneficial microbes, hold water, and improve plant growth.

Around the Yard - Spread a 2" to 6" layer of coarse compost on soil as a mulch, a thick layer of mulch will prevent weed or plant growth. Spread a 1/2" layer of sifted, weed-seed-free compost on turfgrass as a top dressing. Compost can be used any time o the year to improve soil fertility and reduce watering needs.

On House Plants - Sprinkle a thin layer of compost over house plant soil to provide nutrients.

Don't Have a Garden? - You can still make compost and use it on a house plant, give it to a friend, sprinkle it around a street tree, or donate it to a community garden.

Compost Tea - Now that you have a completed pile of compost, it’s Tea Time! Not for you, but for your plants. Place one shovel full of completed compost in a burlap bag or old pillow case, tie it with a string, then sink it into a 5 gallon bucket of fresh water. Let the tea steep for 24 hours and remove bag of compost for later use in the soil. Apply ‘tea’ to plants like a regular watering application. The tea will not burn the leaves and provides a nutritious drink for your houseplants or outside ornamentals

Other Methods to Reduce Yard Waste

If composting doesn’t appeal to you, then consider some other methods you can use around the garden to reduce waste going to the landfill.

Grasscycling - By grasscycling, you will be leaving the freshly mowed clippings on your lawn, as it falls it will create a mulch to help with moisture retention. As the clippings begin to decompose, they will provide nutrients to the grass, reducing the amount of fertilizer needed for a healthy lawn. The method requires more frequent mowing, but the return is less time bagging and dumping the grass clippings. The smaller the grass trimming, the faster it will breakdown. Mulching mowers are designed for this purpose because after they cut, the clipping is further cut into even smaller pieces, then it is blown down into the grass, so it doesn’t sit on top of the lawn. Mulching mowers are great, but not necessary for grasscycling. Less

Mulching - Compost can be created easily by using organic materials as mulch. When laid on the surface of the ground the mulch will slowly breakdown and release some nutrients into the soil. This process takes a longer period of time, but the benefits of moisture retention and lack of effort it takes, make it one of the more simple and easy methods to reduce waste going to the landfill. Materials need to be of organic nature such as leaves, grass clippings, shredded bark, and even shredded newspaper. water and fertilizer will be need with proper Grasscycling.

Burying - You can always bury your organic material. Common methods are trenching, hole, and post hole. This method takes a longer period of time to breakdown, but it enriches the soil directly and nutrients are not lost by gassing off into the atmosphere when the material is left on top of the soil. You’ll want to bury the material about a foot deep to discourage insects and other pests. The depth of the hole will also determine how deep you want to place the nutrients for future gardening. Trenching is when you dig a trench, and back fill it with kitchen scraps. Always cover food waste with six to twelve inches of soil. The hole and posthole method are about the same with the exception that with the posthole you can make your holes on a daily basis.

Biodegradable-Compostable Decomposition Study

Composting Documents (pdf)

Composting - Nature's Way of Recycling (English | Spanish)
Compost Ingredient List (English | Spanish)
Bulk Sources of Compost (English)
CalRecycle Compost Bin Design (English)

Composting Class Resources

Home Composting Made Easy, by C. Forrest McDowell, PhD & Tricia Clark- McDowell (Cortesia Press)
Let It Rot, by Stu Campbell (Storey Book 3rd Edition)
The Rodale Book of Composting, by Gracy Gershuny and Deborah I. Martin (Rodale Press)