Get the dirt on your soil

Think back. Last summer, were you happy with the state of your lawn? How about your vegetable garden? Your trees, shrubs, flowers? Did those thrive?

If not, you could have poor soil – and now’s the time to start fixing it.

But before throwing a bag of fertilizer at the problem, do a soil test. Save time, save the environment, save cash.

If you’ve never tested your soil before, here’s the scoop:

Cyndi Wyskiewicz is a horticulture Extension agent with Virginia Cooperative Extension in Portsmouth. She and other Extension agents across Hampton Roads field a lot of questions. We reached Wyskiewicz in that sleepy spell between winter holidays when gardeners start looking out their windows, thinking about how to make stressed-out plants and raggedy lawns happier in the New Year.

Many go looking for her.

“When people come to me to diagnose problems, one of the first things I want to do is talk about the foundation: How is the soil, what (have) they done with their soil, and have they had a soil test recently? That’s usually the problem. And if they say ‘no,’ I tell them why it’s important,” Wyskiewicz said.

“If you’re starting a new garden or plants are not producing as much, that’s an indication that you should check out the soil.”

A plant growing in good soil is a happy plant, one not as likely to be plagued by plant pests or disease.

Most soil problems have to do with the pH level, or acidity and alkalinity of soil. These factors aren’t evident just by poking around in or looking at soil.

If soil is too acidic, certain plants won’t thrive. The same is true if the alkalinity is too high.

It’s good news to have soil that tests in the middle of the logarithmic scale of 1 to 14, with 7 being neutral. Most plants in our area, including lawns, like a pH of about 6.5 or 7. That’s called “being in the neutral range,” said Wyskiewicz, or not having soil that’s either too acidic nor too alkaline.

To confuse things, there are exceptions, such as rhododendrons or azaleas, blueberries or camellias. These plants all like more acidic soils, with numbers like 4 or 5. But they are special cases.

On the other end, high alkalinity in soil is bad for just about everything, generally speaking, Wyskiewicz said.

The interesting thing about tinkering with the pH level is that lowering or raising it makes nutrients in the soil available to plants. Then plants are better able to absorb either naturally occurring fertilizers or those added to the garden.

There’s at least one other factor: soil structure, or the physical components of soil. It’s a separate issue, Wyskiewicz said, but goes hand in hand with pH.

Soil is made of sand, silt and clay. Too much sand means that nutrients or fertilizer just run through the soil, escaping the reach of plant roots. Too much clay and nutrients trickle down too slowly. Gardeners want soil that holds nutrients within reach of plants.

“So you need to know the percentages of each of those, as well,” she said, “to know how they work together. You add organic matter to soil to loosen it so plants can take up the nutrients.”

Different home test kits cater to do-it-yourself testers. Gardeners take soil samples from their yards and mix a little of this with a little of that; the test will reveal what their soil lacks.

Or gardeners can go a step further and use soil test kits that Cooperative Extension agents like Wyskiewicz make available to the public.

With those kits, soil samples are sent in a paper container to the Virginia Tech Soil Testing Laboratory in Blacksburg for analysis. When tests are complete and results are sent back to gardeners, they are accompanied by recommendations about how to fix any soil problems.

“The soil test that Virginia Tech offers to home gardeners is a basic soil kit that tests the pH and the level of phosphorus and potassium in the soil sample,” Wyskiewicz said.

These kits are available at every agriculture Extension office in Hampton Roads (Portsmouth, Norfolk, Chesapeake, Virginia Beach and the Isle of Wight), and in city libraries and some local garden centers.

The Virginia Tech kit is free, but $10 is charged at the time the soil sample is mailed to Tech’s soil lab. Each kit contains instructions and directions on how to take soil samples and how to include a check for $10 for a basic soil analysis.

The sample-taking is not complicated; instructions are included in the kit. If it’s the soil underneath a lawn that’s in question, a homeowner simply digs down 4 to 6 inches and takes six to eight samples from different areas of the yard. Then the homeowner mixes the samples in a bucket and scoops out a single sample to represent the soil mix under the whole lawn.

The same method is used for a vegetable garden or an entire yard.

On a form included in the kit a homeowner is asked what they are trying to grow – a cool- or warm-season lawn, vegetables, flowers, acid-loving plants or fruits. Answers determine how the soil test results are tailored to the homeowner’s particular needs.

“When you get the reading back,” Wyskiewicz said, “you get a number. If the result is near the ideal, 7, you’re good. It’ll also give you fertilizer guidelines for that crop, how much to put down and the rates as well – for fertilizer or lime. If pH is 6, for example, how much lime to put on to get it closer to what you need for what you’re growing.”

Don’t be shy about soil testing, Wyskiewicz said. Test if you are starting a new bed, and test an established garden every two or three years to see what’s happening in your soil.

And, definitely, if you think you’re having a problem, test the soil every year.

Even after you make changes, it takes a few years for the additions to work their way into the soil. Lime is not an instant fix, she said. It takes time for lime to combine with soil particles and raise the pH. Sometimes you have to add lime twice a year – once in spring and once in fall – before changes can be seen.

Cold winter days are a great time for gardeners to do a soil test.

“They shouldn’t wait until the growing season gets started,” Wyskiewicz said. “They should do it now in January or February. If they wait until April and May, the soil lab takes a while to process everything. The turnaround could be a couple of weeks then; now it’s only three to five days to get a result.”

Like they say, the early bird gets the worm.

Krys Stefansky, (757) 446-2043, krys.stefansky@pilotonline.com