We're a society that believes in testing. We test our cars for emissions, our food for safety, and goodness knows we all experienced more than enough tests in school. So it may seem natural to test our garden soil, but before we put spade to earth, perhaps we should start with the where, when and why.
Why should we care? The most common type of soil testing horticulturists speak of, nutrient analysis, tells us the elements available to the plant, the pH of the soil (relative acidity or alkalinity) and the organic matter content. These measurements provide one part of the picture of soil health (we're ignoring important factors such as soil structure, texture and biology here) and we can then estimate which nutrients are lacking or even in excess for optimal plant growth. That last bit really gets to the point -- we want to know about our soil so that we can help plants grow to their full potential. In this way, gardening is like parenting a child or raising a puppy.
There are several occasions when I suddenly say, "sounds like a good time for a soil test!" The first would be when you start a garden at a new house (or a new house to you). While looking at and touching the soil will give you clues to its potential, there is no way to know the fertility without a nutrient analysis. Sure, you can follow a general sort of recommendation and apply fertilizer, but that's like walking down a dark alley -- you'll probably live to tell about it, but wouldn't some enlightenment just make sense? Once you test, you won't have to do it again for several years.
And if you are growing a crop that demands certain soil characteristics -- blueberries and their need for an acidic soil are a good example -- soil testing can avert plant failure, wasted time, and a harvest of disappointment. Simply said, test before you plant. And if yields are low and plants lackluster, test. Analyzing a plot that used to produce better but which now shows diminishing returns might pinpoint a problem -- just like an MD, testing can enable to the plant doctor in diagnosis and prescription. Lastly, testing can save you money, too, since you'll only buy fertilizer you need.
One way to test your soil is to bring it to us. Take several small samples at a depth of one to four inches from the area in question, mix them together, and drop this composite sample off or mail it to your favorite office of Cornell Cooperative Extension. We'll dry it, fill out the paperwork, and mail it to the testing laboratory. Here in Rensselaer County, we're pleased to use the University of Massachusetts, given their quick response and high accuracy. From the lab both you and I will get a user-friendly report, and you can call me at 272-4210 or email me at firstname.lastname@example.org with any questions. The fee is $20. Your plants will thank you.
David Chinery is the horticultural educator for Cornell Cooperative Extension of Rensselaer County. Reach him at email@example.com.