ANITA STONE: Taking Soil Samples Is A Dirty Job
I detest taking soil samples because I must scoop up dirt from different sections of the yard, and then, after I drop them off or send them via snail mail to those who would analyze them, I have to consult with a horticultural Einstein to interpret the results for me.
Several years ago I made the previous statement to a friend who, like me, did not understand soil sampling. And when a gardener doesn't understand or cannot interpret a soil sample, it's time to call out the "study your soil" squad. So here are a few pointers I have learned over the years.
For starters, you need the proper tools to collect a soil sample. Using stainless steel or chrome-plated tools with plastic buckets is the best because you avoid contaminating the samples with traces of chemical elements from the tools. Keep away from brass, bronze, or galvanized tools because, when analyzed, the soil could show micronutrients from them.
Make sure that the tools and the buckets are clean and free of fertilizer residue or any other material you used previously throughout the growing season. Even a small amount of lime transferred from the tools to the soil can contaminate the sample and produce false results. Before filling the soil box, pulverize and mix the cores thoroughly in the bucket.
Results of testing depend on what is being grown in the landscape or the depth from which samples are collected. For example, where perennial crops are being grown, dig about four inches into the soil so it will measure the lime and fertilizer needs. For areas where field crops are grown, collect samples about the same depth that the field is plowed for planting purposes.
If you decide to plant a vegetable bed, then the suggestion is to dig at least six to eight inches down for a true analysis.
Ideally, samples should be collected three to six months before you plant the bed. You should have the test results in time to plan the lime and fertilization additions if you submit samples on a timely basis.
I have found that the fall is the best time because the soil testers seem to have a lighter workload during that time of year. More people submit their soil samples during springtime. Once you get into the habit of having your soil tested, collect the samples every year about the same time so you can gauge the results prior to planting.
It's a good idea to sample at least once every three years. When you fill out the information on the soil box, make sure you include the proper code identification that is specified on the information sheet.
We know that most soils in our area are naturally acidic and require additional nutrition for optimal plant growth. Acid soils can limit root growth, and unless the acidity and the pH are corrected through liming, applying fertilizer may not correct the situation, according to the North Carolina State University Cooperative Extension.
If your soil pH is between 6.0 and 6.5, except for acid-loving plants, like azaleas and rhododendrons, which require a pH of 5.0 to 5.5, your soil is ready to receive plants. Proper NPK (nitrogen, phosphorous and potassium) is essential for quality plant growth.
Don't allow this soil testing to intimidate you. It will not only benefit your garden and offer beautifying benefits to your plants, but also will aid the environment.
So, like the old-fashioned commercial, "a little dab will do ya'," imitation is the greatest form of flattery -- "a little dig will do ya'."
Anita Stone is a Raleigh freelance writer and a Master Gardener. She may be reached at writer7136@ yahoo.com.
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