From the ground up

Hard work spent improving your soil will pay off big time

In the Garden

November 02, 2003|By Emily Green | Emily Green,Los Angeles Times

So as not to scare us off, garden writers have a tendency to resort to dainty euphemisms. Take "amend the soil" or, alternately, "improve the soil." They mean: Get out and dig. Or, if you have a lot of ground to cover, hit it with one of those urban plows called rototillers.

It isn't just hard work. It's backbreaking. If you haven't done it to your lot, or a certain bed, the bad news is: Now is the time to do it. The good news is, it is the single most important thing you will ever do for your garden and your house and, if done right, it will bear endless rewards.

You can hire people to do it. Sometimes we have to. But if you possibly can, do it yourself. Working the earth is the best way to get to know your property, whose soil profile can change completely from one end of a 150-foot-long lot to the other. It's also the beginning of real gardening. The most basic thing for any garden isn't plant choice, or the elegant turn of a garden path, or a nicely enameled bird bath, it's soil condition.

Once digging is done, you are now ankle deep in the fundament from which everything in the garden grows -- or doesn't. Start gardening in improved soil, and nature opens up. Suddenly we see how plants work and understand what they need, from the roots up and not just from the ground level up.

More often than not, the soil we start with will be seriously depleted. For much of the 20th century, many of us believed not in soil condition, but in better living through chemistry. Recent-ly, a group of very unlikely people -- football coaches -- were among the first urban groundsmen to look to antique farming and gardening methods, and to insist that regimens of lawn chemicals be augmented by good old-fashioned amendments. They noticed that leaving cut grass on the ground, called grass cycling, and adding manure and compost every year softened the soil and reduced the number of players' bone fractures. For homeowners, the same principle means that children's falls can end with bruised egos and not broken bones.

The modern yard

Urbanization has transformed soil in our yards. When builders come in, the first thing they do is cart away loose topsoil, then wet and steamroller what's left to make it as rocklike as possible. Once they've laid roads and foundations, they might bring back some of the native soil to layer around houses, but chances are they will import a thin layer of compost from a recycling yard, rake it into a thin, ephemeral layer, unroll some turf and call it a lawn.

Once a home is built, compacted soil becomes treacherous. A tiny settlement in the grade can redirect rainfall away from the curb and back into the foundation. One of the best ways to correct this is to grade and rehabilitate the topsoil, an absorbent layer that will capture water much the way a towel stops a spill flooding across a hard kitchen floor. The water then has time to percolate down to the compacted soil below.

The first step to working with the soil that builders leave behind is determining its character -- sand, silt or clay.

Clay and sand present opposite problems that have the same solution: working in organic matter. Sand particles are large and loose. Water runs straight through them and nutrients are washed out from underneath the root system.

Meanwhile, clay particles are tiny and fine and tend to clump together. Compacted urban clay can be so hard, bullets would ricochet off it. Rainwater and irrigation run straight off the lot and down the drain. Once it finally does absorb water, it takes another eternity to dry out.

When broken up, the particles stop binding with one another and reconnect with organic matter, creating large, porous particles that can then, and only then, conduct water, oxygen and nutrients to the plants.

Whether bulking up sand or fluffing up clay, there is no shame in doing it one bed at a time, even one a season.

Dig and mix

The soil should be turned to a depth of six inches, about the length of the best tool for the job -- a small-faced shovel called a "lady shovel." Any slender shovel, even post-hole diggers, will work.

If it is clay and too dense to penetrate with a shovel, break it up first with a pick. After picking out the rubble and weeds, spread the smelly stuff, politely known as improvements. The tilled area should be covered by two inches of rotted organic stuff, including compost, to loosen the soil and manure with nitrogen to feed it. The names on the sacks of soils sold in home improvement stores are confusing. Mushroom compost. Bark compost. Plain old compost. Topper. Orchid mix. Patio mix.

If you use a compost, match every four sacks with one of manure for nitrogen. Or select a premixed version of the two. Do not buy potting soil, patio mix or any of those souped-up soils. These are fine for houseplants and their white fillers -- perlite, pumice or Styrofoam -- help lighten the weight of patio pots, but they have no place in garden soil.

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