Building a Compost Pile

What is “compost”?

Compost is the term applied to organic matter – such as leaves, weeds, grass clippings, and the like – which has been sufficiently decayed to form a light, crumbly mold. In making compost in a compost heap, soil and manure are often mixed with the vegetable matter.

Should the average home gardener have a compost heap?

Yes, by all means. It is about the only adequate substitute for the “well-rotted” manure which is less available than it used to be.

What materials are used in making a compost heap?

Plant refuse: cornstalks, cabbage stems, dead foliage, and discarded vegetables; leaves, grass cuttings, garbage, soil, manure (in fact, any vegetable matter that will decay), plus lime and complete fertilizers. Weeds, even when seeding, may be used if the heap is to be remade at the end of each 3 months, turning it inside out so that every part of the heap is completely decomposed before use. A heap treated in this way is so well rotted that most seeds and insect eggs are destroyed.

How is a compost heap constructed?

Heaps 4 ft. wide and 6 ft. long are convenient size for the small place. Dig out this area to a depth of from 12 to 18 ins. and throw the soil to one side. The bottom layer should be cornstalks, cabbage stems, and other coarse material, tamped down. Over this lay 2 or 3 ins. of soil, and then 2 or 3 ins. of manure, if available. Peat moss can be used if manure cannot be had. Sprinkle raw ground limestone over every other layer at the rate of a quart to a wheelbarrow-load of compost material. On alternate layers apply a complete chemical fertilizer, about a quart to each alternate layer. Add layers of leaves, cuttings, weeds, etc., with a layer of soil, manure, or peat moss every 12 to 18 ins. Keep sides even but sloping very gradually inward toward top. When all material has been placed in layers, soak thoroughly with hose and cover entirely with 3 ins. soil, well firmed down. The top is left saucer-shaped to receive and absorb rainfall. Do not let heap dry out at any time. At end of 3 months remake entire heap, turning inside out, if rapid decomposition is desired.

What length of time is required for a well-made compost heap to rot?

Four months to a year, depending on its composition and whether or not ingredients have been added to hasten decay; usually about 9 months.

What is a good formula for making a compost pile break down quickly?

I understand lime should not be used as it causes loss of nitrogen. Lime should be used, but should not come in immediate contact with added fertilizer.

Is the use of a compost starter advisable?

Most of those sold are only fertilizers plus limestone. Your own fertilizer will be much cheaper. Others are bacterial cultures. Bacteria can be added for nothing with garden soil.

How often should a new compost heap be started?

To maintain a constant supply of compost, a new heap should be started every 6 months.

How is rotted compost used in gardening?

It should be sieved through a coarse (1-in.) screen and then diluted with 3 or 4 parts of garden soil. It can be worked into the garden by applying a 1-1/2 in. layer and cultivating it into the upper 6 ins. of soil. For a lawn dressing, apply the sieved compost without dilution with soil.

How should decomposed compost be removed from the heap?

Cut sections down vertically with a spade, leaving straight, clean sides where it has been removed. Sift through a 1-in. sifter and save coarse siftings for a new compost heap.

Must I use compost in my garden?

I have no space for a compost pile. Unless you can afford to buy peat moss in large amounts, compost is the only way to supply organic matter. For those with limited space, composting in the plastic bags used for disposing of lawn clippings and other wastes will solve the problem. Mix leaves, lawn clippings, or even garbage with about a handful of a good mixed fertilizer, plus a pint or two of good garden soil to each bushel. Dried leaves should be sprinkled enough to moisten them through, but not make them soggy. Clippings and garbage will not need additional moisture. Seal the materials in a plastic bag and tie shut. Stack the bags in any convenient place (I have used a garage and a root cellar). At temperatures above 70 degrees F., material will be ready for use in three to four months.

Pests and Diseases in the Compost Pile

In making a compost heap, how can we avoid carrying over diseases of previous year, as tomato and potato blight, etc.? Do not use diseased tops, vines, or fruits for composting, unless special care is taken in “turning” the heap.

Some of the waste vegetable matter I put in my compost heap had a lot of aphids or similar insects on it. I put lime and superphosphate with the compost. Will the aphids be killed during the winter?

The adults will probably die, but the eggs may carry over. At the time of making the compost the vegetable matter should have been sprayed with malathion. However, if the heap is turned “inside out” every 3 months and if every part is thus thoroughly fermented, most insects and diseases will be destroyed.

Does it do any harm to put moldy fruit, vegetables, or mildewed shrubs and leaves into the compost?

Any vegetable matter which is not infected with disease or infested with insects may be used safely for composting. Molds resulting from decay do no harm.

Explain the chemistry of the compost heap. Would the pests it might harbor outweigh the advantages for a small (50 x 100 ft.) garden?

A compost heap is a mixture of soil, fertilizer, and organic matter. In decomposing, the combination does not always get rid of all diseases and pests. To save organic matter, a compost pile is worth having.

Composting Terms You Should Know

The process of composting is very straightforward – a pile of organic matter rots to form healthy mulch. But there are a few terms you will come across while learning to compost, and here are a few brief explanations to help you talk compost.

Aerobic Aerobic microbes are the tiny critters that do a lot of your composting for you. They take care of business quickly, but they need oxygen to function. Turning your pile aerates and loosens it, encouraging these microbes to keep working your compost for you.

Anaerobic On the other hand, anaerobic microbes work well without oxygen. They work quietly and slowly in dense piles of organic matter, and may cause your compost to smell bad. However, they do an excellent job of transforming organic waste into healthy mulch.

C/N Ratio This is the carbon to nitrogen ratio. Carbon-rich materials are dry and bulky, while nitrogen-rich materials are moist and dense. Compost ready for the garden should have a ratio of about 10:1.

Cold Pile Cold piles are slow piles. If there isn’t enough nitrogen material, or if the pile isn’t regularly turned, microbes in the compost are not able to multiply well enough to generate the necessary heat for a good rate of decomposition.

Decomposers The wonderful bacteria and microbes that operate to consume and process your waste, transforming it into nutrient-rich compost.

Finished Compost When your pile consists of very dark, almost black, sweet-smelling, crumbly material, it’s done. Often you will find this material in the middle of the pile when you turn it. Any nearly decomposed material can also be mulched into the garden, where it will continue to decompose. Anything not near decomposition can be used to get your next pile going.

Hot Pile A good aerobic pile of compost can reach temperatures of up to 160 degrees Fahrenheit. Under these conditions, most diseases and seeds won’t survive. It is the work of the aerobic microbes processing your organic waste that causes the pile to heat up, and means your pile will decompose at a good rate.

Humus Basically, for the gardener, humus is interchangeable with finished compost. But science makes a couple of distinctions: humus is shapeless (amorphous) and colloidal (referring to the size of the particles).

Loam Refers to a certain soil composition. Loam is a combination of coarse sand, fine clay, and medium-sized silt. Many plants thrive in loam. Adding compost to your regular soil will leave you with many of the healthy properties of loam.

Sheet Composting If you don’t have room to establish a compost pile – or if you don’t want to – you can use the technique of sheet composting to add organic mulch to your garden. Spread grass clippings, leaves, or any other compost ingredients in a layer over your soil, and dig them through. The materials will decompose directly into your soil.