Composting Benefits

By September 18, 2010In The Garden


Benefits of using compost as an organic fertilizer and mulch:

  • Making compost is cheap or free.
  • Compost improves soil structure, texture, and aeration.
  • As a mulch, compost helps the soil retain water.
  • Compost is an organic fertilizer that improves soil and plants.
  • Compost stimulates healthy root development.
  • A compost pile is an excellent means of disposing of organic debris, leaves, food wastes, grass clippings, etc.
  • Organic compost improves the environment.
  • Organic fertilizer increases vegetable garden yield.

Your compost pile should be located on a level well-drained site in full sun.  Plan on each pile being about 3-4 feet wide and 3-4 feet tall.  There are all kinds of ways to contain your pile or it doesn’t need to be contained at all.  I have several piles in different locations depending on where I’m going to use the compost.  Entire books have been written on this subject and I will only be able to give you the basics here.  I can suggest a book called “Lasagna Gardening” by Pat Lanza.  It has nothing more to do with Lasagna than the fact that in making lasagna you layer your ingredients.

In broad terms, there are two major kinds of food that composting microbes need:

  1. ‘Browns’ are dry and dead plant materials such as straw, dry brown weeds, autumn leaves, and wood chips or sawdust. Because they tend to be dry, browns often need to be moistened before they are put into a compost system. (see below for more detail)
  2. ‘Greens’ are fresh (and often green) plant materials such as green weeds from the garden, kitchen fruit and vegetable scraps, green leaves, coffee grounds and tea bags, fresh horse manure, etc. Compared to browns, greens have more nitrogen in them. (see below for more detail)

A good mix of browns and greens is the best nutritional balance for the microbes.  I usually try to use a layer of two parts brown to one part green. This mix also helps out with the aeration and amount of water in the pile. Browns, for instance, tend to be bulky and promote good aeration. Greens, on the other hand, are typically high in moisture, and balance out the dry nature of the browns.

Shredded or chopped materials will breakdown faster; you can run over piles of leaves with your lawn mower, put larger brown materials through a chipper or shredder or put your household scraps in a blender or food processor before adding them to the pile.

Starting your pile with something on the bottom to allow air circulation will help the process to move along quicker.  You can use an old pallet or a grid work of larger limbs or branches on the bottom layer and start layering the brown and green.  Once your pile is built (about 3-4 ft. high), add enough water to dampen everything and in time it should start to heat up.  It should be warm to the touch.  Once this starts happening you can let it set until it cools down and start using the compost in many ways or let it continue to “work” by turning the pile and letting it go through several heat and cool down cycles for finer compost.  The more you turn the pile and the more manure that’s in it, the faster it will decompose.

You can also continue to compost throughout the cold months, it just won’t be heating up like it does in the summer.  You will have a great pile of organic goodies to start out with in the spring, just mix it into an existing pile of start a new one.

The following items can be added to your compost pile:

Actually, it’s usually easier to leave grass clippings in the lawn, where they will decompose and benefit the soil directly. However, they can be composted, too. Be cautious to add grass clippings in very thin layers, or thoroughly mix them in with other compost ingredients, as they otherwise tend to become slimy and matted down, excluding air from the pile. Fresh grass clippings are high in nitrogen, making them a ‘green’ compost ingredient.

Farmers are often very happy to get rid of spoiled hay bales that have been out in the rain, and will give them away or sell them at a low price. Grass hay will probably contain a lot of seed, which can resprout in your garden. Alfalfa hay will compost very readily. The greener the hay, the more nitrogen it contains. Be sure that any hay you plan to compost is well-moistened prior to addition to the pile.

Fruit and vegetable peels/rinds, tea bags, coffee grounds, eggshells, and similar materials are great stuff to compost. They tend to be high in nitrogen (this puts them in the ‘greens’ category), and are usually quite soft and moist. As such, kitchen wastes need to be mixed in with drier/bulkier materials to allow complete air penetration. Avoid composting meat scraps, fatty food wastes, milk products, and bones — these materials are very attractive to pests.

If you live in an area where autumn leaves are still thrown away as garbage, cash in on the bounty each year by acquiring your neighbors’ leaves! Generally, leaves are an excellent compost ingredient. They can mat down and exclude air, though, so be sure that any clumps are thoroughly broken up, or that the leaves are only used in very thin layers. Dead, dry leaves are in the ‘browns’ category, while living green leaves contain abundant nitrogen and are considered ‘greens’.

Dry straw is a good material for helping to keep a compost pile aerated, because it tends to create lots of passageways for air to get into the pile. Be sure to wet the straw, as it is very slow to decompose otherwise. Straw is definitely a ‘brown’ and also requires mixture with ‘greens’ to break down quickly. Many stables use straw as a bedding material for horses — straw that has undergone this treatment is mixed in with horse manure and breaks down more quickly.

Many types of weeds and old garden plants can be composted. Avoid weeds that have begun to go to seed, as seeds may survive all but the hottest compost piles. Green weeds are (you guessed it) a ‘green’, while dead brown weeds are a ‘brown’.

Most farm animal waste can be used in your compost pile.

Wood products belong in the ‘browns’ category, because they are fairly low in nitrogen. Some sawdust, especially from broadleaved/deciduous trees, will break down quickly in an active compost pile. Others, especially from coniferous trees, will take longer to decay. Stir sawdust thoroughly into the pile or use very thin layers. Coarse wood chips will very slowly decay, and are probably better used as mulch unless you have lots of time to wait. Be sure not to compost chips or sawdust from any sort of chemically-treated wood — you could be adding toxics like arsenic to your pile if you do.

Do not add the following items to the compost pile:

Many plant disease organisms are killed by consistent hot composting, but it’s difficult to make sure that every speck of the diseased material gets fully composted. It’s best not to compost diseased plant material at all, to avoid reinfecting next year’s garden.

Human feces can contain disease organisms that will make people very sick.

These materials are very attractive to pests (in an urban setting, this could mean rats…). In addition, fatty food wastes can be very slow to break down, because the fat can exclude the air that composting microbes need to do their work.
Morning glory/bindweed, sheep sorrel, ivy, several kinds of grasses, and some other plants can resprout from their roots and/or stems in the compost pile. Just when you thought you had them all chopped up, you’d actually helped them to multiply! Don’t compost these weeds unless they are completely dead and dry (you may want to leave them in a sunny place for a couple of weeks before composting). Remember also that composting weeds that have gone to seed will create weeds in next year’s garden, unless a very hot pile temperature can be maintained to kill the seeds.

Dog and cat feces may carry diseases that can infect humans. It is best NEVER to use them in compost piles. Some people do bury them 8″ deep in the soil, but ONLY in areas where food crops are never grown.