What Kind Of Soil Do We Have?
Jun 28th, 2011 Posted in Chris and Lise, Gardening Tips | Comments OffRecently, I found the most wonderful book at a Library book sale. Published by Storey Publishing, the book is Secrets to Great Soil: A Grower’s Guide to Composting, Mulching, and Creating Healthy, Fertile Soil for Your Garden and Lawn by Elizabeth P. Stell. If you have found yourself confused about how to improve your soil, this book is the answer. It’s become my Bible in this year’s effort to get our garden soil into shape.
The first step, according to Stell, is to figure out what kind of soil you have, so in an effort to answer that question I did a couple soil tests on the soil in our plot. This soil is somewhat better than what would be there otherwise, but is still pretty close to the basic garden dirt that we’re all dealing with.
The first test I did was a “structure” test. I took a set of four samples from different parts of the garden, and took them in such a way that I got a slice of dirt from the surface down about 6 inches. I mixed the samples together and then put about a cup and a half in a mason jar, to which I added water to the very top of the jar. I then added 1/2 teaspoon of ‘natural’ dishwashing liquid and shook the jar. Over the next couple days, I watched and waited as sediment layers developed. The results are shown below:
My amateur assessment of what I saw is that the dirt I sampled is about 97% homogeneous sandy loam, with another 1-2% dark organic matter, and a trace amount of outright silt. (The silt is that fine powder that lies on top of most of our garden plots and tends to blow away when it hasn’t rained in a while). The sand in our sandy loam is fine grained with just a bit of grittiness when wet.
One noteworthy tidbit: it took a long time for the some of the silt to settle out of solution. Moreover, the water that remained never did completely clarify — some of the silty clay remained in solution a week after the test.
pH Test Tube
On to the pH and nutrient tests. I will admit, I did not spend top dollar on my test kit. It was a RapiTest product that cost $5.98 at Agway and has enough test tubes and test chemical capsules to do 4 pH tests and 2 each for Potassium, Phosphorus and Nitrogen. After much mixing, shaking and adding of water (making me feel a little like a Junior Chemist), I succeeded in capturing some results.
Here’s how the least improved soil from our garden plot tested out:
pH – very acid – 5.0 or below
Nitrogen (N) – very low
Phosphorus (P) – low
Potassium or Potash (K) – very low
I was not at all surprised by these results. The soil samples I took were from areas where I hadn’t added any soil amendments recently, so it was to be expected that soil fertility would be low. I was a little surprised by the acidity as I would have thought that the absence of leaves and evergreen needles in our plots natural compost would have kept it more neutral. Not so, as it turns out. My sample tested unmistakably acid.
While a number of vegetables will grow in soil with a pH of 5.0 and up, my researches tell me that they are happiest in the 6.0 – 7.0 range. However, Stell says that if you add lots of organic matter (humus, compost, leaf mold, manure), your plants will be able to tolerate greater acidity. The task for me is to figure out how to raise the pH of our plot into the neutral range. I’d like to do it without adding lime, so now I’m looking at mulches again to determine which is the most ‘neutralizing.’
For starters, fertilizer is more than just a chemical emulsion that you apply. Chemical fertilizer may provide a cheap shot of “nutrition” for your plants but it won’t do anything for your soil, except possibly kill it. Real fertilizing is more about the soil itself — creating healhty, living soil full of microorganisms and organic matter. You can’t get that out of a bottle, and that’s why learning about soil amendment and natural plant food is so important. In The Permaculture Way, Graham Bell throws out a variety of ideas, most of them cheap and easy to make use of.
