Compost is organic materials (grass clippings, leaves and vegetable food scraps) that have decomposed into a rich soil conditioner. Composting is the process of combining the right ingredients and conditions that allow microorganisms to make compost. It's really just a way of "recycling" organic materials.
Compost provides many benefits:
* Compost improves the drainage and aeration of clay soils, and reduces the likelihood of
* Compost increases the moisture and nutrient holding capacity of sandy soils, and reduces
drought damage to plants.
* Compost helps keep nutrients in the soil near the plant's roots.
* Compost keeps soil from crusting on top, thus helping seeds to sprout and water to soak in more easily.
Many of your neighbors are already composting, and you can too! To make composting easier, this article covers the tools, containers and organic materials you will need; how compost happens; and how to become the envy of your neighbors after your compost is done.
Who composted first? It's hard to know, it was used by Roman and Asian cultures, over 2,000 years ago! The Roman empire fell, but composting lives on!
In the 1800's, famed agricultural chemist and educator George Washington Carver helped many people understand the nutritional value and great taste of peanuts. But peanuts were not his only interest; he also taught people of his day that compost was important to gardens, and it saved money. He said, "make your own fertilizer...compost can be had with little labor and practically no cash outlay".
You don't need a bunch of fancy tools to compost -- just a pitchfork or shovel to turn the compost, a bucket or hose to water the compost, and a compost bin.
City of Minneapolis Ordinance requires that compost piles be contained by some type of compost bin. Piles without bins can become unsightly and may not be able to generate enough heat to safely decompose organic material. Many local garden centers or hardware stores have compost bins, or you can make one.
* Woven wire bins Bins made of woven wire or snow fence are popular because they are inexpensive,
simple to build, and easy to move and store. Steel posts can be used for corner supports.
* Turning bins These bins make turning the compost easier because they give you something to turn the
compost into. And, with a multi-bin composter, you can start new compost while the first batch is still
Whatever you use, your compost bin should be at least 3'x3'x3' to generate sufficient heat for composting.
The space you can have for compost bins is limited by the size of your property as follows:
* The maximum size for a compost area on lots with a residential structure is fifteen (15) cubic yards.
* The maximum size on lots without a residential structure shall be twenty-five (25) cubic yards for lots under (10,000) square feet and one hundred twenty (120) cubic yards for lots over ten thousand (10,000) square feet.
Where is a good place to put your compost bin? In your backyard!! Partial shading is ideal. This will keep your compost from drying out too quickly. Avoid placing the bin under the edge of a roof, where rainwater may run off and over-water the pile. City Ordinance requires that your bin be placed at least one foot from any property line, and 20 feet from any habitable building other than your own home. See Compost Containers in the Accessory Structure & Uses section of the Zoning Code for more info.
Successful composting combines the materials below, in the right proportions, to give microorganisms such as bacteria and fungi an environment in which to thrive. Microorganisms are essential to the composting process and are naturally found on "greens" and "browns".
Greens -- Organic material like fruit and vegetable waste and garden plants. Greens are high in nitrogen,
and provide the building blocks for the protein that microorganisms need to reproduce.
Browns -- Organic material like leaves, straw, woody plants and woodchips. Browns are high in carbon and
provide the carbon source for microorganisms.
Water -- The material in the compost bin should be like a damp sponge - wet to the touch, so that you get
just a drop or so of water when you squeeze a handful of compost. If the compost gets too wet, air will
not get to the organisms. Without enough water, the organisms will not thrive.
Oxygen -- Those little microorganisms need to breathe too! Without enough oxygen your pile may begin to
smell badly. Build your pile in alternating layers of greens and browns in order to build in air-flow. Loose
browns materials give the pile texture and help create air-flow between layers of kitchen waste.
Other ingredients… the good and the bad
Okay to add -- rice, grains from home brewing, coffee grounds, crushed eggshells, fruit remains, tea bags, vegetable scraps. Vegetable and fruit scraps are high in nitrogen and moisture and tend to become compacted, so air cannot get to the microorganisms. Pay special attention if you are composting fruit and vegetables. Grass clippings are considered "Greens" in the spring when they have more nitrogen, and "Browns" the rest of the season.
Note: Please pay special attention to plants that are poisonous to animals. Make sure these items are kept within the compost pile and/or are composted through a commercial composting facility. Examples of plants that are dangerous for house pets (cats and dogs) include: fruit pits, garlic, hops (from brewing), potato and tomato leaves and stems, and more. Visit the Animal Humane Society's website or the American Society for the Prevention of Cruelty to Animals' website for a list of dangerous and poisonous plants for animals.
Do NOT add -- meat, fats, oils, grease, bones, whole eggs, milk or other dairy products, human or pet wastes, pesticides, herbicides, noxious weeds, diseased plant material in which the disease vector cannot cannot be rendered harmless through the composting process, and any other mixed municipal solid waste that may cause a public health risk or create nuisance conditions. City of Minneapolis Ordinance prohibits these materials in home composting bins.
Layering the bin:
Step 1: Start with a 2"-3" layer of small sticks or wood chips or a 4"-8" layer of browns. This will help airflow
up through the pile.
Step 2: Add a 4"-8" layer of greens and moisten.
Step 3: Add a 4"-8" layer of browns and moisten. Tip: Break up sticks before you place them in the pile.
Long sticks make turning the pile difficult, and smaller pieces will break down quicker.
Step 4: Sprinkle on a thin layer of soil or finished compost. (optional)
Step 5: Repeat steps two through four until the bin is full.
If you already have greens and browns mixed together, you can combine steps 2 and 3.
IMPORTANT: If you don't have enough materials to make 4"-8" layers at any one time, simply layer in your green and brown materials equal proportion. For example, every time you add a handful of kitchen waste to the pile, cover it with a handful of leaves or woodchips.
After a few days, your pile will begin to heat up as the microorganisms thrive and your pile begins to decompose. Ideally, your pile should heat to about 140-160 degrees to kill weed seeds or diseases in garden plants. (Your bin must be at least 3'x3'x3' and have the right mix of ingredients in order to heat up properly.)
How often you mix the compost depends on how quickly you want a compost product. The more frequently the materials are mixed, the more air will get to the microorganisms, the more your green and brown materials will properly blend, and the faster they will be able to decompose the materials.
When mixing the pile, be sure to:
* Turn the materials at the outside or the edges of the bin to the inside, so that all the material will be
properly heated and composted.
* If your pile is not moist like a damp sponge, be sure to add water as you turn the pile.
After you turn the pile, the heat will increase, and peak after 4 to 7 days. To maintain a hot pile (one that is rapidly decomposing) turn the pile each time it begins to cool.
After being turned several times, the pile will no longer heat up -- the work of the microorganisms is done. Just let your compost pile sit as insects and earthworms complete the job.
How long will it take? That's up to you. Finished compost can be made in as fast as one month under ideal conditions, or as long as 12 to 24 months. The time it takes depends on how often you turn the compost, the balance of greens and browns, and the moisture level.
There are a variety of ways you can use your finished compost:
As Soil Enrichment in Vegetable and Flower Gardens
Add from 1"-3" of compost to your soil and work it in well. Adding compost will help soil keep nutrients near the plants roots.
As Mulch Around Trees, Shrubs, or Plants
Apply a 3"-6" layer of compost around the base at the plants. Compost makes an ideal mulch for annual and perennial gardens.
Compost used as a mulch will help suppress weeds, reduce soil erosion, moderate the soil temperature, and conserve soil moisture. Compost will also make a cozy home for earthworms, who help aerate the soil.
As a Substitute for Peat Moss
Mix one part compost and two parts potting soil.
Composting is pretty low tech, but you may encounter a few problems at first. Here are some common problems and solutions:
The compost has a bad odor
Solution: Cover the pile with a layer of wood chips or leaves. The pile may be very odorous while you're turning it, so cover it quickly with a 6" layer of wood chips or leaves when you are done turning if you notice a bad smell.
Pile is not composting quickly.
Solution: Pile may have dried out. Mix the pile and moisten as you turn the compost. Pile may also not have enough green or brown material. Usually you want to add green and brown material in equal parts by volume.
The compost is moist and sweet smelling but still won't heat up
Solution: Not enough greens. Add a nitrogen source like grass, vegetable waste, or cow manure.
The compost is damp and warm only in the very center.
Solution: Pile is too small. Be sure your pile is at least 3'x3'x3'.
Unwanted pests are attracted to the pile
Solution: They smell food scraps. Stop adding food scraps, or cover the food scraps with a thicker layer wood chips or leaves each time you add to the pile.
Unwanted pests are nesting in the pile
Solution: Turn the pile.
Neighbors keep asking why your garden looks so great
Solution: They don't compost. Show them your compost bin, your compost and share this article with them.
Here are a few of the many books about composting that are available:
* "Backyard Composting: Your complete guide to recycling yard clippings" by Harmonious Technologies
* "Let it rot! The Gardener's Guide to Composting" by Stu Campbell
* "Rodale Guide to Composting" by Jerry Minnich and Marjorie Hunt
* "Worms Eat My Garbage" by Mary Appelhof
Hennepin County Environmental Services: www.hennepin.us and search Backyard Composting
Minnesota Extension Service for their guide.
Minnesota Pollution Control Agency: Start composting in your backyard.
For inspiration and great information about composting, we thank the Seattle Solid Waste Utility, King County, Washington, the City of Plymouth, and the Minnesota Extension Service of Hennepin County.
Last updated Sep 5, 2017