What Is Good Garden Loam?

When soil requirements are specified for various kinds of gardening needs, reference is frequently made to “good soil,” “ordinary garden loam,” “good garden soil,” or “good garden loam.”

For example a potting soil mixture for fuchsias calls for two parts “good garden loam.” Exactly what kind of soil is meant? What is “good garden loam?”

We might say it is the kind of soil that raises a good crop of lettuce, beans, beets, carrots, or other vegetables. Or that produces fine zinnias, cosmos, or marigolds.


But that isn’t definite enough.

Soil Builds Over Time

Examine a handful of “good garden loam.” It is dark in color, mellow and crumbly in texture, soft and moist to the touch.

Soil has been long in the making. Countless ages ago the sun and the wind, the air and the water started the disintegration of the earth’s rocky crust. Lichens and mosses got a foothold in the crumbly fragments in the crevices of the rocks… lived, died and decayed.

As centuries passed, soil formation continued. More rock crumbled to make mineral soil, and more plant and animal residue mixed with it, the organic part.

It became a living thing teeming with minute organisms such as helpful bacteria. Forest soils were found to be different from grassland soils, and swampland soils differed from dryland soils.

Part of this was because of the very nature of the plant life above it (which in time was added to the soil) and part of it was because of the size and kind of rock fragments.

Soils Get a Number Grade

Soil scientists use a number of terms to designate or classify the various kinds of soil. Clay soils contain very fine particles of disintegrated rock. It is known as a heavy, cold soil and is slow to warm up in the spring.

It is capable of holding much water which is an asset during dry seasons but harmful during wet years. If one does not cultivate such soil after each rain, a baked crust forms on top. When worked while too wet, hard brick-like lumps form.

Sandy soils are called light, warm soils although by actual weight they are heavier than clay soils. They contain gritty rock particles that are much larger than those found in clay.

Sandy soils are easy to work. They warm up quickly in the spring.

This is important, for not only can a gardener start garden activities sooner but the helpful bacteria commence work sooner and plant food is made available earlier.

A disadvantage is that a sandy soil is not retentive of moisture. Water not only pours through it as easily as through a sieve, but it takes much of the plant food with it.

The combination of clay soils and sandy soils makes loam soils. If clay is predominant, it is known as a clay loam. If there is more sand than clay, it is known as sandy loam. The most desirable soil contains approximately equal amounts.

“Good garden loam” must be porous enough to provide good drainage and permit air to enter, yet be spongy enough to retain an ample supply of moisture.

Conditions must be favorable for the growth of helpful soil bacteria. Humus is added to loam to provide these things. Its value can hardly be overestimated.

Humus is Natural

Humus is decomposed vegetable and animal matter. It occurs naturally in forests and grasslands where leaves, twigs, grasses, weeds and other material accumulate and gradually decay. A little is added each year and a like amount is used up each year.

To make and keep our garden loam “good” we must do the same thing.

All garden refuse except diseased plants, all leaves and other material should not be discarded, but piled and allowed to decay thoroughly. Well rotted manure and soil added in layers to such piles of refuse and kept moist will hasten the process.

When all is well decayed, spread a layer (the thicker the better) of this humus over the garden and borders and mix it well with the top soil. Loam (a mixture of clay soil and sandy soil) combined with plenty of humus makes ‘“good garden loam.”

Clay soil + sandy soil = loam
Clay soil + sandy soil + humus = good garden loam

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