It’s almost spring and now is a good time to get your soil tested if you didn’t do it last fall. This gives you just enough time to interpret the results and make some changes before you fill your beds with plants. Otherwise you will have to wait for late summer or fall.
I bet you didn’t know that soil science is also a study in philosophy and culture. Different groups have conflicting viewpoints of how soils work like the organic community, biodynamic farming and even hired professional farm consultants. The most influential group is the agricultural colleges and land grant universities.
University teaching is geared towards chemical agriculture and their experts do not necessarily subscribe to some of the competing ideas from the other groups. Unfortunately the typical University material downplays the differences in food quality despite abundant evidence to the contrary. The belief that an apple is an apple is an apple works well for industry, but not for the consumer. I’ve found the most useful information actually comes from a handful of agricultural consultants and black sheep professors. The ag-consultants jobs are dependent upon results, and not upon published papers, and results are what we care most about. My article on pH was a small example of this conflict in ideas.
Because of this, not all soil testing labs are equal. Understandably, most labs are oriented towards chemical agriculture and work well for that particular use. I hold the belief that our results can far exceed that and picking the right soil test is part of the puzzle. I’m over simplifying here but there are basically two groups of soil test labs out there. The first are those that attempt to identify total nutrients using strong acids to extract the minerals from the sample, this is the type normally used by universities and chemical-ag. The second group are those that try to identify what they call available nutrients by using weak acids, under the belief that this more closely represents what plant roots have access to. Both types have value for different reasons, but I put a lot more emphasis behind available nutrients.
The other thing to consider is what nutrients are tested for, and not just how they are tested. My local soil test lab only covers various forms of Nitrogen, Phosphorous and Potassium. These are the big three nutrients from chemical-ag philosopy, also knows as NPK. Unfortunately you can not get a best of class product using the NPK method. Great produce is only possible in well balanced soil, which means testing for a whole lot more. At a minimum the test should cover at least 10 nutrients if not 20 or more, 3 is just grossly insufficient.
Soil balancing is a very big topic, but I don’t want you to wait for me to write 20 more articles when you can make the necessary improvements to your own gardens now. Go get a soil test and pay the extra cost for the recommendations. Please remember that soil testing is just one of many tools we will be using. It is not the final and only thing you can do to improve your food quality.
Soil Test Labs I recommend:
For more information in book form on the topic that are well suited for gardeners:
- The Intelligent Gardener by Steve Solomon
- The Art of Balancing Soil Nutrients by William McKibben
- The Ideal Soil by Michael Astera