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Garden Composting

note_pin.gif (247 bytes)    Planter's compost  is a mix of grass clippings, weeds, pine needles, and leftover composted soil, including well-composted kitchen scraps and manure and and a little limestone to balance the acidity from pine needles.  This  'black gold' is fundamental for a healthy garden, so it gets a lot of space and some attention.   Visit the BBS Gardening  Group for a good understanding about worms, pathogens, and other components of a good compost pile.

What is Compost?

Source:  Virginia Cooperative Extension, Virginia Technical Institute
Author: Diane Relf, Extension Specialist, Environmental Horticulture

Composting is a degradation process brought about by bacteria and fungus organisms. Large amounts of organic kitchen, garden, lawn, and/or farm refuse can be reduced in a relatively short time to a pile of black, crumbly humus which makes an ideal soil conditioner. Compost added regularly to soil will inevitably benefit the soil. The soil's structure will improve, since humus contains substances which cause aggregation (sticking together) of soil particles. In a clay soil this means that the microscopic individual particles will be clumped together and more air spaces will be opened up between clumps. Without these air spaces the clay particles stick tightly to each other, forming a nearly impenetrable barrier to water and gases. This is why clay is so sticky when wet and hard when dry. In sandy soils, the large sand particles are clumped with humus too, the humus adding its nutrient- and moisture-holding capacity. Normally, water and nitrogen fertilizers leach quickly from sandy soil, making it necessary to add them frequently.

A less widely recognized benefit from compost is that it contains humic and other organic acids which help to degrade compounds naturally present in the soil into the simpler form that plants use. These elements, or ions, can then be held by the humus particles, which contain many ion exchange sites on their surfaces. The ions are released into soil water, and plant roots are able to take them up.

Because there are so many ion exchange sites on humus particles, humus increases the buffering capacity of the soil. This condition helps to prevent rapid leaching of lime and nutrients as well as reducing the effects of over-liming and over-fertilizing. For example, when a soil's pH is increased too much by adding too many wood ashes, the most economical way to correct the condition is generally to add compost, which will absorb (take up on the surface) the extra ions that produce the high pH. (compost itself is somewhat acid because of the acidic products made by microorganisms.) In other words, compost buffers the effects of other soil additives.

Compost and other organic matter turns the soil dark brown or blackish and increases heat-absorbing capabilities to a small extent. Compost reduces soil erosion because it allows water to percolate into lower soil layers, rather than puddle on top and then run off. This quality also reduces crusting of soil. Compost provides food for earthworms, soil insects, and microorganisms, many of which will, over the years, help balance the populations of less desirable soil fauna. Mycorrhizal fungi, which have been proven to benefit plants through their association with plant roots, are also prolific in high humus soil. Finally, the products from the breakdown of plant and animal refuse contain many fertilizing elements in and of themselves, including trace elements not available from commonly used synthetic fertilizers.

Making Compost

To make compost regularly, it is helpful to have compost bins in some form. You can construct two bins out of planks or concrete blocks. Make the bins about 4 feet high, 4 feet wide, and as long as desired, and open at one end for easy access. Leave spaces between blocks or planks for aeration. Accumulate plant refuse in one bin while the composting process is taking place in the other. A third bin may be desirable for near-finished or finished compost storage.

A simple, portable compost bin can be made with three or four used freight pallets, which are simply stood on their ends in a square or open square and lashed or otherwise held together. This type of bin can be disassembled for easy turning and emptying and then reassembled around the new pile. A chicken wire cage supported by three or four wooden stakes will also work satisfactorily, but is less sturdy.

There are also ready-made and kit composters available, including slat-sided cylinders into which refuse is added from above and compost removed at ground level. Rotating barrels for easy turning are also available; gardeners who have limited strength may find either of these types easier to deal with than the standard compost bin.

Whichever type of compost maker you use, it's a good idea to make use of the nutrients which leach out from under the pile. This is easily done by locating the composter in the garden (which also reduces hauling time) or under a large fruit tree. Or, if the compost pile is on a slope, trenching can direct the run-off.

Start your compost pile with a 3-inch layer of coarse plant mate- rial such as small twigs or chopped corn stalks. This will aid in aeration and drainage. On top of this, put a layer of plant and kitchen refuse - leaves, straw, weeds, waste from garden plants, husks, coffee grounds, crushed egg shells, canning wastes, etc. It is a good idea not to use meat wastes because they will attract digging animals. Next, add a layer of nitrogen-rich material. This can be fresh manure if available, fresh grass clippings (not too thick a layer, as they will mat), fresh hay, or succulent green weeds. Nitrogenous materials are necessary for the microorganisms to make proteins. Add more in the form of synthetic nitrogen fertilizer (1/2 cup 10-10-10 per 6" layer), blood meal (also 1/2 cup per 6" layer), or cottonseed meal (1 cup per 6" layer). The latter two are expensive if purchased in the typical five-pound bags available in garden centers, but cottonseed meal can be found at a very reasonable price if purchased in bulk at a farm supply store. If a more alkaline compost is desired, add 1 pint of ground limestone per square yard of surface area. Liming will also help reduce odors.

To inoculate the compost pile, about one inch of soil should be added for each 6" layer of plant wastes to supply microorganisms for the composting process, unless enough soil is included on roots of weeds and expired vegetable plants, or in manure. If the waste materials are free of soil for the most part, a sprinkling of soil, a compost starter, or a layer of old compost or good gardening soil added to each layer will introduce necessary microorganism.

Repeat the layers of plant material and nitrogenous material as many times as needed to use all the plant refuse available. If using a ready-made composter, follow the manufacturer's instructions. Keep the top of the pile lower in the center to cause water to move into the pile rather than to run off.

Water the pile as often as necessary to keep the contents moist, but not soaking wet. Within a few days, the pile should heat up significantly, to about 160 degrees F. This temperature will kill many weed seeds and harmful organisms, and is a necessary stage in composting. If the pile fails to heat, it may lack nitrogen or moisture. The pile will also decrease in size after a few weeks if it is composting properly.

If you smell ammonia it may mean that the materials in the pile are too tightly packed or that the pile is too wet; i.e., there is not enough air. Turn the heap, adding some coarser material, and start again.

The pile should be forked over after about a month (two weeks if the material is shredded), putting the outside materials on the inside and vice versa to make sure everything gets broken down. Turn again 5-6 weeks later. The plant materials should decompose into good compost in about 4 or 5 months in warm weather, but may take longer under cool or dry conditions. Composting may be completed in 1 or 2 months if the materials are shredded, kept moist, and turned several times to provide good aeration.

When compost is finished it will be black and crumbly, like good soil, with a pleasant, earthy smell. Only a few leftover corncobs or stalks will remain undecayed. These can be sifted out and added to the next batch. For use in potting mixtures, a relatively fine sieve (1/4" hardware cloth) will take out the larger chunks. Otherwise, the compost can be spread in the garden as it is and dug or tilled under, ready to offer your soil and plants its many virtues.

If you need only a small amount of compost, you can use a plastic trash bag to compost relatively fine material such as leaves, lawn clippings or chopped garden refuse. Make layers as in a compost pile, or mix all materials together. Add 2 quarts of water to dry material (one quart if it is quite moist or succulent). Tie the bag and turn it over every few weeks to aerate the material and distribute the moisture.

Sheet composting is another method of making compost. A layer of organic materials of about 3-4 inches is spread over the soil, then covered with a 2-inch layer of soil. The organic material is allowed to decay at least three months prior to cultivating. Sheet composting on an unused portion of your garden in the fall can provide an enriched area for spring planting.

             Search on Virginia Tech Extension Serv., Information Resources for your topic.

How to compost

Select a place to put a bin or pile. Some general tips for choosing a site include: 1. Good drainage below the pile or bin, 2. Protection from fierce winds, 3. Ease of access for adding materials to the pile, 4. Relatively level ground, 5. Sunny spot( don't let your pile dry out though), 6. Shady spot (Does not dry out as fast)

Construct a compost pile (on the ground) or a compost bin. Building a pile is easy to do and inexpensive (actually it's free). The only materials needed are organic materials (food), Air, and Water. You may also need garden gloves, a pitchfork, and a shovel to handle the decaying materials. The drawbacks to just building a pile are animals can easily raid your pile especially if the pile contains food scraps and it is not as tidy opposed to composting in a bin. It is not as fast as using a bin. Using a bin is the preferred way to compost although you may have to purchase materials to build the bin. Obviously a bin is somewhat contained so it is cleaner and prevents animal pests from stealing future humus. There are many bins available to purchase or simply build your own. Its as easy as taking snow fencing and four posts and constructing 3'x3'x3' square. Do not build a bin larger than 5'x5'x5' for a bin of this size prevents air from circulating through the pile.

The process in which organic materials are converted into a usable media is caused by microbes. Aerobic (requiring Oxygen) and Anaerobic (can not live in oxygen). Aerobic microbes decompose materials quicker and thus they are preferred. Anaerobic bacteria breakdown materials as well but release a strong stench. Microbes are found in soil and manure. More microbes will enter your pile if your pile is on the earth and not elevated off of the ground.

Adding slightly decomposed manure from vegetarian animals will hasten the decomposition process especially for decomposing woody (high carbon) materials. you want to mix organic materials with a carbon:nitrogen ratio in mind. A ratio of 30:1 is an optimal level. Also keep in mind the greater variety of materials used will result in finished compost with a greater variety of essential nutrients. Before filling your bin or pile, chop or shred the materials into 1 inch pieces (quickens decomposition) do not make materials smaller to avoid compaction.

So when assembling your pile alternate layers of carbon materials (dead leaves, tree branches), nitrogen (fresh cut grass, food scraps) and add a few hand fulls of soil and manure throughout the pile. To avoid compaction make the layers 3"-5" thick. Piles containing Aerobic bacteria (hot piles) can reach temperatures of 194 degrees Fahrenheit under these conditions pathogens and weed seeds are destroyed. Additionally at these temps the bacteria are working their hardest to decompose the materials.

You can measure the heat of your pile with a compost thermometer after your compost has reached an optimal temp turn and mix the pile so all ingredients have a chance to be in the center of the pile (the hottest part of the pile). You don't need a thermometer, as a rule of thumb rotate your pile every two weeks.

You also want moisture in your pile. Optimal moisture levels are between 40-60% moisture. An easy way to gauge the moisture of a pile is to grab a handful of compost and squeeze it. It should have the moisture of a wrung out sponge. Cover your pile during rainy conditions and if you have to add water to the pile, poke holes in your pile or mix water in as you turn the pile.

Using a hot pile can produce finished compost within 6 weeks. A cold pile (without oxygen) can take up to 2 years to produce humus. So I recommend building a hot pile.

Quick Checklist: 1. Select a site to put your pile or bin. 2. Build your pile or bin. 3. Feed your pile organic materials in a 30:1 carbon : nitrogen ratio. 4. Alternate layers of green and browns and do not forget the manure. 5. 40-60% moisture throughout the pile. 6. Good air flow through the pile.

So after maintaining your pile and following the rules of composting you should have a rich, earthy smelling substance or humus. You are now ready to apply your finished compost!

    Search for 'compost' on Ohio State Univ. PlantFacts

Compost Tea

Compost tea is the enhanced liquid extract of quality compost. The process involves successful extraction of the microorganisms present in good compost. A good compost tea reflects the same diversity of microorganisms present in the compost and if properly made contains a much higher concentration of these organisms by volume. Successful extraction depends on a number of factors, the most important being proper aeration, agitation, time, and the required nutrition for rapid growth of the microorganisms. Good compost tea has many beneficial characteristics, the most promising of which is the suppression of numerous plant diseases. Compost tea can be applied to the foliage or the soil.

Steps: How to make compost tea

1. Fill a metal bucket one-third full of finished compost.
2. Add water to the top of the bucket.
3. Let the mixture steep for three to four days.
4. Strain the mixture through cheesecloth or other porous fabric into another container. Add any remaining solids to the garden or return them to the compost bin.
5. Dilute the remaining liquid with water so it's the color of weak tea.
6. Apply compost tea according to each plant's requirements (check seed packets and gardening books for details). For best results, work early in the morning or on cloudy days.