How To Use Compost: Lawn Trees, and Garden

For thousands of years, gardeners have been piling organic wastes—weeds, leaves, grass clippings, manures —in heaps to decompose into soil-enriching compost.

In a compost heap, dead materials are transformed into substances that nourish new life.

How to Use CompostPin

Compost increases the fertility of the soil and improves its physical structure.

It loosens hard-packed clays, binds sandy soil, aids water retention, and releases major and minor nutrients to plant roots.

No other substance has so many beneficial effects on the soil’s chemical, physical and biological properties.

Compost, then, is a basic tool for building fertile soil and thus for growing fine plants.

Made and used properly, it is excellent for everything from sowing seeds to feeding trees.

General Rules For Using Compost

The more liberally you apply compost, the better your results will be.

A 2- or even 3-inch application on a given area each year is not too much, especially if your soil is poor to start with.

Half-rotted, fibrous compost is best applied in the fall. Poor soil’s structure and fertility will greatly improve if you spade it up 12″ to 18″ inches deep and incorporate large amounts of this compost.

It can also be spread on the soil surface and worked with a rotary tiller to a depth of 4″ to 6″ inches. The material will continue decomposing through the winter.

Some gardeners like to plant a green manure crop to add fertility when it is dug or tilled under in the spring; others leave a mulch of hay or similar material on top of the soil.

Finished compost, which is notably crumbly and has a rich, dark color, may be applied a few weeks before planting.

Work it through a half-inch screen, returning to the compost heap any coarse pieces that won’t go through the mesh.

Save the very fine material for seeding and potted plant mixtures.

Mixed with topsoil, well-rotted compost is ideal for top-dressing and side-dressing growing plants.

Used this way, it gradually supplies nutrients to the plant roots near the surface and acts as a mulch to protect the soil from eroding rain and temperature extremes.

Another method of supplementary feeding during the growing season is compost watering.

Many of the nutrients in compost are readily soluble. Fill watering can half full of compost, add water and stir, and sprinkle all your plants liberally.

A cheesecloth bag of compost suspended in a barrel or similar container will give you a rich, amber-colored solution for feeding all plants.

Your New, Deep-Rooted Lawn

For a thick, deep-rooted lawn that defies crabgrass and drouth, use plenty of compost to make the lawn and maintain it.

When building a new lawn, spread a 2-inch layer of compost and fertilizer and mix it thoroughly into the top 6” inches of soil.

Do this early in the fall, using finished compost, and sow the lawn in cool weather.

If it is necessary to start making your lawn in the spring, sow a temporary covering like Italian ryegrass, which will look neat until it is turned under in the fall; then work in the compost and make a permanent lawn.

A patchy old lawn is easily renovated. Dig up the bare spots about 2” inches deep, mix in ample finished compost, tamp down, and water well before seeding.

An established lawn should be fed with compost regularly every spring and fall.

One of the best methods is to go over the grass with a spike-tooth aerator—the deeper the spikes, the better—then spread compost that has been put through a quarter-inch screen.

Rake this into the holes made by the aerator and water well.

Fertilizers should be spread and watered simultaneously, preferably of the slow-acting organic type.

Trees And Shrubs

For the excellent growth of woody plants, soil building is a must. But, as the experts say, “A $10 hole for a 1.00 plant” is the key to beautiful, healthy trees and shrubs.

Dig the planting hole two or three times the depth and diameter of the root ball, and use a planting mixture of equal parts of topsoil, finished compost, and peat moss or leaf mold.

Fill this in evenly all around the roots, tamping down each spadeful.

Two inches of compost can then be spread on the top, out to the maximum reach of the branches.

A mulch of peat moss, hay, ground corncobs, buckwheat hulls, or leaves over the compost will help keep the soil moist and add more fertility and humus as it decomposes.

Roses, by the way, amazingly thrive if copious amounts of compost—two parts of compost to one of soil in planting—and a 6-inch mulch of hay or straw are used.

For regular maintenance of young trees and shrubs, spread several inches of compost each year and mulch.

Use pine-needle or oak-leaf compost for evergreens that need acid soil, and mulch them with the same materials.

Always give the soil a thorough soaking before mulching, then soak the mulch well, too.

Stones can be put on top of the mulch—they make a neat appearance, and the cool, moist conditions under them encourage earthworms and other organisms that break down the organic matter and release its fertility.

To keep rodents from nesting near the trunk and damaging it, leave a bare space 2′ feet from the trunk outwards.

This “ring” method is ideal for fruit trees, ornamentals, and berry plants.

Many an old, sickly fruit tree has been brought back to a vigorous hearing by a heavy composting and mulching program, combined with judicious pruning.

And commercial orchardists and numerous home fruit-growers have proven that the amount and number of sprays can be greatly reduced when such a program is followed.

Another method of feeding older trees is to auger holes a foot deep and a few feet apart, each encircling the tree, and pack these with mature compost.

Or you can push a fork into the soil at intervals, working it back and forth to crack the earth, then pour compost water into the cracks.

The Flower Garden

All new flower beds should be dug up at least 18” inches deep and a 4-inch layer of compost—if the soil is poor—worked into the soil. This will make it light, rich, and crumbly, well-drained but moisture-retaining.

Your seeds will sprout better if compost is used generously in planting. Bulbs, too, like a handful or two of compost in the bottom of the hole, covered with an inch of sand or soil.

Early in spring, lightly cultivate the top 2” or 3” inches of soil in your annual, perennial, and bulb beds, and work in plenty of compost.

Then use finely screened compost, mixed with an equal amount of topsoil, as an inch-thick mulch when your plants have come up.

Feed them with compost water every two weeks all season.

The Vegetable Garden

Vegetables grow bigger and taste far more delicious when compost is used lavishly in growing them. Disease and insect troubles are greatly lessened, too.

So, if you want luscious vegetables, dig in all the half-rotted compost you can get in the fall, work in finished compost two weeks before planting, and use it generously in the planting holes and furrows.

When the plants come up, mix ripe compost with soil and side-dress them heavily; repeat this in summer.

Or, as an alternative, mulch the rows with lots of semi-finished compost covered with raw compost materials such as hay, grass clippings, and the like.

It seems you can’t get too much compost, provided it is made from a large variety of materials that will ensure a balance of nutrient elements.

Vegetables have actually been grown in pure compost, with amazing results.

Starting Seeds

Compost put through a fine sieve and mixed with equal amounts of fine sand and soil is an excellent seed-sowing medium.

Somewhat coarser compost may be used in the bottom of the flats for good drainage. No fertilizer is necessary.

When the seedlings have developed their first true leaves, you can transplant them into a richer mixture of half compost and half topsoil.

Use the same mixture when transplanting them outdoors, and give them frequent waterings with a dilute starter solution of compost water to speed their early growth.


Porous soil is vital for potted plants to ensure good water retention and aeration. 

Two parts of loam to one each of sand and crumbly compost make an excellent general potting mixture.

Double the amount of sand for cactuses and the compost for humus-requiring plants like African violets.

Use pine-needle or oak-leaf compost for acid-loving plants such as azaleas and gardenias.

The fertilizer most houseplants will require is a biweekly feeding of weak compost water.

Repotting a fresh soil-sand compost mixture every year or two is advisable for most potted plants.

Plants in window and planter boxes will get the same benefit if an inch or so of the old soil is scratched out every spring and replaced with a mixture of equal parts of fresh topsoil and compost.

This procedure should be repeated again in summer for vigorously growing or flowering plants.

44659 by Thomas Powell