Soil Testing: Why it’s Important and How to Do it

A plant can only be as healthy as the soil it sits in.

This old agricultural adage underlies how critical it is to maintain healthy soil. Whether you’re trying to grow turf, a vegetable garden, or trees and other foliage, the soil will be a deciding factor in your success.
Each plant has a unique soil profile-that is, the ideal conditions of the soil for that specific plant. Sustainable lawn care begins by understanding that plants will grow better when the soil profile matches their needs. Promoting growth in your lawn, then, means altering the conditions of the soil. Of course, this means that grass will also grow healthier and also faster, meaning you’ll find you have to take care of your lawn a lot more than you usually once did – if this could perhaps be a pain you could look into different mowers such as these Reel Rollers that could make your mowing a lot less trouble.

But how will you know what needs to change in your soil unless you know what the current state of your soil is?

That’s where soil testing comes in.

By collecting a representative sample of the soil in your yard (or, for landscapers, the yard of a client), you can know the exact conditions of your current soil profile. Then you can begin to alter the soil to match the needs of your plants. Some gardeners keep bags of soil in their sheds in Pittsburgh, or wherever they live, so it’s a good idea to take samples of those bags of soil too, just to get a clear understanding of the soil they’ve got.

Soil tests have their roots in the agricultural community, where they’ve been around for a long time. This is because good, healthy soil will reduce the number of chemicals needed. If the soil is healthy, the plants will be healthy. And healthy plants generally have much less issue with insects, pests, and disease. If you think your plants need a little extra help to grow and become healthy, check out agron.io.

How to Collect an Appropriate Soil Sample
In order to be effective, your soil sample needs to be representative of the whole area you’re trying to test. Pulling samples only from one area of the lawn will not produce accurate results. As you pick spots to pull your samples from, try to choose spots from every part of the testing area. You’ll need 10 or more different locations to pull from.

Once you’ve chosen the locations, take your probe (like this one) and push it into the ground. You’ll want to sink the tip of the probe several inches below the surface. Then, spin the probe around and pull it out of the ground. The probe should have pulled a few inches of soil up with it. This is one of your samples.

Before you put the sample into your collection can, do a little soil test of your own. Check for the amount of thatch (undecomposed grass clippings, roots, etc.) on the top of your sample. If you see a half-inch or more of thatch at the top of your soil sample, that’s bad. The more thatch, the more susceptible your plants will be to damage by insect or disease. A healthy lawn will see only a tiny bit of thatch at the top of the sample.

Also check over your sample for roots. Does it look like the plants are developing deep, healthy roots? Or are the roots shriveled and small. Shriveled roots could indicate the plants are dehydrated or that they are not pulling the necessary nutrients from the soil.

Once you’ve checked for thatch and root health, put this soil sample into your collection can and move on to the next one. Collect 10-12 different samples from around your lawn.

Try to use the same level of pressure each time you pull a sample. One thing your test is trying to discover is the compaction of the soil-how dense is it? This will affect the amount of oxygen your plants are getting through their roots, as well as the oxygen getting to the biology of the soil. Even pressure for each sample will help to ensure you get an accurate sense of the soil’s compaction.

Also, don’t take samples from around the edges of walkways, driveways, or the street. These samples might be skewed by stone, salt, or other debris spilled over from the concrete.

Once you’ve collected all of your samples (remember, 10-12 at least), mix them together in your collection can. This mixture is what you’ll send to the lab. With your mixing tool, make sure to break up any soil chunks you see in the mixture. Then send 1 cup of the mixture off to the lab.

Where to Send the Sample
There are many different institutions to send your soil sample off to. Often state agricultural schools provide a soil testing service for little or no charge. This may be the cheapest way to get a test done. Many private laboratories also provide soil testing.

Most of these institutions are still using a test that’s designed primarily for agricultural use, rather than for lawn or turf care. So even if you send in a sample for turf growth or a vegetable garden, they’ll still do the procedures for an agricultural test.

This test is good at determining what nutrients are in your soil. It will give you an accurate measure of the makeup of your soil. However, just because a nutrient is in your soil does not mean that nutrient is available for plant use. It’s pretty common for several factors to make those nutrients “lock-up” and be unusable by the plant. This means that these agricultural tests may give you a false reading. The results may look like your lawn is healthy (full of nutrients) when, in fact, it isn’t.

There are 6 or 7 labs throughout the country that have a different test procedure for lawn and turf care. This version of the soil test will tell you what nutrients in the soil are available for plant use. It’s much more accurate and will give you better results.

Soil testing is key to sustainable lawn care. By making yourself aware of what’s in your soil, you can make informed decisions about the best lawn and turf care practices.

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