Q: I am starting a brand new garden in a place that has been grass, not garden. How can I get it off to a good start?

Q: What can I add to my vegetable garden to improve the soil?

Q: What soil amendments are the best?

A: I agree that no garden can be better than its soil. However, there are many kinds of gardens and many kinds of soil. My first suggestion to any aspiring gardener is to be realistic. Work with the soil you have, and suit what you grow to the character of your soil.

The basic characteristics of a soil cannot be changed by a gardener. If the dirt is sandy and well-drained, it will stay that way. Water will run through quickly, leaving dry soil in a matter of hours. If soil is clay with fine particles, it will be rich in minerals but will be hard to dry out once wet, hard to wet again when dry and cracked.

The very best soils for gardening are the loams, which have a high percentage of organic matter. (Five percent organic matter is a high number.) Most of any soil is smashed or ground rock of some kind. It is the small percentage of decayed plant and animal pieces, the organic matter, which supports the growth of green plants.

Therein lies the secret of garden soil. If a soil amendment is by nature organic, it will add to the organic percentage and help the soil grow better plants. Homemade compost is among the best of the soil amendments. No gardener I know has ever managed to create a surplus of compost. It gets spread thinly on garden beds until it runs out; then it is supplemented with leaves, manure, and commercial compost.

Additionally, if organic materials are spread on top of the soil and left there, not dug in, they are the most help to the soil organisms. These minute organisms like best to feed at their own rate and do not like to be flipped upside down with a shovel or whirled through tiller blades. If their population is well fed and housed, soil microorganisms help to grow garden plants.

If materials laid on garden soil as mulch are fairly woody — that is, if they include a lot of bark, wood chips, or small sticks — the decay of those woody pieces can occupy microorganisms which otherwise would be helping plants.

When woody mulches remain a separate layer on top of the dirt, there is no problem. One population of microorganisms works on breaking down the wood; a second population, living in the dirt underneath, feeds the plant roots. If the woody pieces are tilled into the soil, there are no longer two microorganism populations, just one trying to do two jobs, and plant roots may go hungry.

It would never be wrong to add a little fertilizer to a woody mulch. The nitrogen in the fertilizer will help to decay the wood.

One other soil characteristic which is unchanging and very important is where the soil chemistry lies on the acid–alkaline continuum. Attempts to grow acid-loving plants in alkaline soil, or those which need lime in acid soils, are doomed. It is possible to fill a small hole with soil completely different from the native variety. As soon as a plant's roots try to venture outside the hole, they get sick.

Anna Pavord, the British garden guru, says, "Happy gardeners go with the flow and grow plants that like their soil. Megalomaniacs find this a difficult precept to accept. They dig pits in their gardens and fill them with a different kind of soil, hoping to hoodwink plants into believing that everything is as it should be. For a while this works. But gradually, the soil's true constituents leach into the pretend patch and take it over. Or the plant's roots meander outside the cordon sanitaire and choke on the unfamiliar food."

Fortunately for local gardeners, local soils are mostly in the middle of the acid to alkaline range. They will grow all the plants of the midrange. Only the lovers of the extremities need to be avoided.

My second recommendation about improving soil is to be patient. For soil which is not nutrient rich, trees, shrubs and perennial flowers will be the most successful. Greedy annuals, which must grow from start to finish in one season, will do better once soil has been improved. No matter what is growing, plants will all grow better after a garden has existed some years. Expect a first-year garden to be better than whatever it replaced. Expect garden soil which is consciously improved to grow better and better plants from year to year.

Q: What does it mean if seed is labeled organic?

A: It means that those seeds have been grown under all the conditions specified by the USDA which apply to commercial growing of organic foods. The regulations are very specific. For example, suppose you want to produce seeds which are to be sold as organic. Not only must your plants be grown by organic rules, but also they must be grown far enough from any conventional variety that there can be no accidental contamination. Bees must not be able to reach an organically grown plant, carrying pollen from a conventionally grown one. Even the irrigating water must meet the organic standards. Pelleted seeds are fine seeds covered with a clay-based substance to make them easier to handle. Organic pelleted seeds must be coated with a substance approved by the National Organic Program.

Some seed companies do not sell seeds which can be labeled as organic. More companies sell a mixture of organic and conventional varieties. A few companies — mostly very small ones — sell only organic seeds.

Organic seed production is not an absolute guarantee that seeds are healthy, or even that they are what they are supposed to be. For instance, a seed company which wants to grow an organic strain of salad bowl lettuce must be careful to have a large population of those lettuce plants which are making the seeds for sale. Small numbers of plants will soon become inbred and sickly.

Within a dozen years or so, seeds of the same name would hardly resemble ones grown by other seed producers. Growing a stable seed variety, year after year, requires a great deal of breeding knowledge, a large number of plants from which to select seed, and diligent selection of only the best seed for sale. This must happen not once but every single year.