Growing Veggies? Test for Nutrients, pH Levels, Toxins

Analyze Soil for pH, Nutrients and Toxins

Analyze Soil for pH, Nutrients and Toxins

Although home kits are available to test your soil acidity and moisture content, you'll get a more complete picture by sending samples to a lab.

Photo by: Aleksandar Blanusa /

Aleksandar Blanusa /

Although home kits are available to test your soil acidity and moisture content, you'll get a more complete picture by sending samples to a lab.

Once you’ve tested your soil’s moisture levels and composition, there’s just one more step: Make sure it has the ingredients it needs to grow a healthy garden (and nothing extra that you don’t want.)

pH and Nutrients: Two major factors determine how well plants can grow in your garden soil:

  • pH Levels – Soils that are too acidic – or not acidic enough – can leave plants susceptible to disease, inhibit them from absorbing essential nutrients, and can lead to smaller, weaker, and less-productive vegetable plants. While all plants have slightly different optimal pH levels, most will do well with levels between 6.5 and 7 (considered a neutral pH). Any garden store will sell pH kits – they’re inexpensive and easy to use.
  • Nutrient levels -  Minerals like phosphorus, potassium, magnesium and calcium are vital to a healthy soil. An easy way to evaluate your soils’ health: After the ground has warmed up to at least 55 – 60 degrees, dig a hole about a foot wide and a foot deep in an area that’s moist, but not wet. Sift through the dirt. If you find at least ten worms, it’s a pretty good indicator that your soil has all the necessary ingredients to produce a healthy garden. Fewer worms doesn’t necessarily mean the soil is unhealthy, but you may want to consider further testing. Check with your community’s cooperative extension office.

Toxins: Until recently, I really didn’t see why we should test our garden soil for toxins. We live in a small, semi-rural town, far away from waste sites. But the other day I was reading an online gardening forum, and somebody mentioned that railroad ties are full of lead. It so happens that the previous owners of our house created a makeshift patio from about a dozen railroad ties, and they’re less than 6 feet from the area I was planning to plant a garden in this year! Needless to say, I’m sending our soil out to be tested next week. As it turns out, getting soil tested for toxins like lead, arsenic and petroleum can be relatively easy and inexpensive. If there are heavy metals that are known to be an issue in your region (lead is a common one), there’s a good chance your local extension office will provide low-cost testing.

If your soil turns out to be unhealthy or just plain scary, you may be able to improve the soil to make it more productive – or safer. Stay tuned for a post on amending soil soon.

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