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GREENING

Laying the groundwork for glory

October 02, 2003|Emily Green | Times Staff Writer

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." These don't mean "take it to confession" or "send it to finishing school." 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, at the opening of fall planting season and before winter rain. 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. You find where the builder dumped his rubble, where owls pooped out squirrel skulls, where a rock outcropping was chopped off by developers, maybe even where a stream once ran. 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.

For The Record
Los Angeles Times Wednesday October 08, 2003 Home Edition Main News Part A Page 2 National Desk 1 inches; 43 words Type of Material: Correction
Soil quality -- An article on improving garden soil that ran in the Home section Thursday incorrectly stated that free compost sites were run by Los Angeles County. The service is run by the Los Angeles City Bureau of Sanitation, not the county.
For The Record
Los Angeles Times Thursday October 09, 2003 Home Edition Home Part F Page 8 Features Desk 1 inches; 44 words Type of Material: Correction
Soil quality -- A story on improving garden soil that ran in the Home section last Thursday incorrectly stated that free compost sites were run by Los Angeles County. The service is run by the Los Angeles City Bureau of Sanitation, not the county.

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. Recently, 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. It was a question of buoyancy. 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 bone fractures. For homeowners, the same principle means that children's falls can end with bruised egos and not broken bones.

Our soil wasn't always hard. Back when Southern California was tribal land, then cultivated farmland, its soil didn't need improvement. It had some of the best topsoil in the world, and geologists had more names for it than France has cheeses. Soper gravelly sandy loam. Milsholm loam. Mocho loam. Saugus loam. And so on.

But urbanization has transformed it. 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 rock-like as possible. Once they've laid roads and building 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. It will be one of three things: sand, silt or clay, says Jim Downer, University of California cooperative extension agent for Ventura County. Foothill soils tend to be rocky variations on sand or decomposing mountain. Silt is rare. Most of L.A. soil is variants of 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. Organic matter in sand will help hold water, plus provide nutrients.

Meanwhile, clay particles are tiny and fine and tend to clump together. Compacted urban clay can be so hard, bullets would ricochet off of it. Rainwater and irrigation run straight off the lot and down the drain. Once this impervious stuff finally does absorb water, it takes another eternity to dry out. When in this saturated state, there is so little oxygen that it can effectively drown plants.

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. This also allows lots of beneficial bacteria and fungi to do their things, which research out of Ohio State University shows help control plant diseases.

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