Garden Soil Tests

Soil tests tell you the nutrient levels in your garden soil, a plant version of the nutrient guides on packaged foods. They also note pH and organic content, two factors important to overall smooth sailing from the ground up. To have your soil tested, call your local Cooperative Extension Service, often listed under federal or county government in the phone book. Ask them how to get a soil-testing kit, which contains a soil-collecting bag and instructions. Follow the directions precisely for an accurate report.

Don't add more fertilizer to your soil than the soil test says is necessary.
©2007 Jupiter Images Corporation
Don't add more fertilizer to your soil than
the soil test says is necessary.

Skip the Big Dig
Kill off sod or dense weeds by layering newspaper, compost, and mulch directly on the garden site. This treatment cuts off the sunlight to unwanted vegetation, which will eventually decay and add organic matter to the garden. The newspaper decomposes, too. (What a bargain!)

The results may come as a chart full of numbers, which can be a little intimidating at first. But if you look carefully for the following, you can begin to interpret these numbers:

  • If the percentage of organic matter is under 5 percent, the garden needs extra compost.

  • Nutrients will be listed separately, possibly in parts per million. Sometimes they are also rated as available in high, medium,
    or low levels. If an element or two comes in on the low side, you'll want to add a fertilizer that replaces what's lacking.

  • Soil pH refers to the acidity of the soil. Ratings below 7 are acidic soils. From 6 to 7 are slightly acidic, the most fertile pH range. Above 7 is alkaline or basic soil, which can become infertile above pH 8. Excessively acidic and alkaline soils can be treated to make them more moderate and productive.

Add only the nutrients your soil test says are necessary. More is not always better when it comes to plant nutrients. Don't feel compelled to add a little bit more of a fertilizer that promises great results. Too much of any one nutrient can actually produce toxic results, akin to diseases or worse. Buy only what's required and save the rest of your money for a better use, like more plants. However, you can use lots of compost, the more the better, in most cases.

If your soil's pH is on the acidic or alkaline side, you might want to make some changes to the soil for the benefit of your garden. Keep reading to learn about soil pH levels and how to adjust them.

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