How to test your soil

You can buy the most attractive plants in the greenhouse or order the best seeds, but they won't produce if your garden lacks nutrients. A soil test is the best way to check growing potential and determine which, if any, fertilizers are needed. It eliminates the guesswork about soil chemistry.

A routine soil test is inexpensive — generally around $10 for residential growers. No charge is assessed commercial crop growers in many agricultural states.

Price includes a soil test kit with written instructions, an appraisal of at least nine different elements (including pH), an explanation of the findings, suggested amendments, and the return postage.

"It's a one- or two-day process," says Steve Heckendorn, whose soil-testing lab at Virginia Tech processed 56,000 samples in each of the past two years.

"When fertilizer prices jumped, so did the increase in farm samples (tested)," Heckendorn says. "I attribute the increase of residential lawn and garden samples to greater interest in gardening and educating homeowners and lawn care companies on how they can contribute in reducing water pollution."

Here's how it's done:

– Pick up a soil test kit from your county extension office. Many garden centers also stock them.

– Soil samples can be taken any time of year, even in winter, provided you can poke a trowel into the frozen ground. It's probably best done in spring or fall, however, so the recommended amendments can be added well before the plants go in. Mix the sediment from at least five different sites. Discard extraneous grass or litter.

– Do not take samples when the ground is unusually wet. Also, do not mix soil with specimens taken from where the ground has been heavily limed or fertilized. Those should be packaged separately.

– Mail soil samples and fee to the laboratory address specified on the kit.

For tips about choosing and using fertilizers on the lawn and in the garden, read Choosing the right fertilizer for your lawn or garden.

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