Soil Sense

by Diana Alfuth, horticulture educator for Pierce and St. Croix counties UW-Extension

Sure, your yard and garden soil is frozen and covered with snow — out of sight, out of mind. But now is the BEST time to plan your garden, and that includes planning for great soil!

How long has it been since you’ve had a professional soil test done? Never? You should do a soil test every four to five years, and it’s a small investment for a great, productive garden. While you can purchase soil-testing kits at garden centers, some of them have questionable reliability. It’s better to send a soil sample into a reputable lab to be sure you are getting accurate results. Your local UW-Extension office can help with information on how to collect and submit a soil sample.

soil_test_richmond_lawn_careWithout an accurate soil test, it’s impossible to know what your soil needs! Soil test results will tell you how much phosphorus and potassium — two of the main plant nutrients — are in your soil. If you have adequate amounts, there is no reason to spend money on these fertilizers.

Perhaps the most important thing your soil test tells you is the pH. The pH matters because if it is too high or too low for the plants you are trying to grow, they are not able to take up the nutrients they need. You can have nutrient deficiencies or toxicity if your pH is out of whack. Most garden plants are happy with a pH somewhere between 6.2 and 7.5, but some, such as blueberries, prefer a pH below 5.0. Plants, such as pin oak or white pine, will have yellow foliage caused by an iron deficiency if the pH is too alkaline, even if there’s plenty of iron in the soil.soil-Tesing-e1436464562358

A soil test from the UW soil lab will tell you not only your pH, phosphorous, and potassium levels, but exactly  how much of what to add to get your soil where it needs to be to grow the plants you want to grow. Plan now to do a soil test as soon as the ground thaws in spring.


3 thoughts on “Soil Sense

  1. I have never done a soil test because I work with so many different plants that tell me more than I want to know about the soil. If one does not say it, another will. At the farm, where we grow only a few specie, the soil is more mysterious. If it is lacking in some way, I would not know it.. Our crops happen to get what they need. (We only grow stock plants and field grown specimens in the ground.) There are af few plants that we do not grow because they would not like the soil, and a few others that do not get planted in sandy spots. So many of my colleagues who grow field crops or orchards are more involved with their soil, and test it often.


  2. Our members are primarily home gardeners — many with smaller gardens in the city where the nutrients are used up pretty quickly. As a result, we recommend regular soil tests before overloading with fertilizer that may or may not be appropriate.


  3. Pingback: Enjoy Beautiful Clematis | Garden Snips

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