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Gardening Blog - My soil test

2.16.18 Getting Nerdy about the Soil

Wow! I received the interesting soil test results from Michigan State University and read about what my soil has too much of and what it lacks. Since I am pretty clueless regarding what the results really indicate, I called the MSU Extension Gardening Hotline 1.888.678.3464 and spoke with Danielle, who is a bubbly bundle of gardening knowledge, and of course a Master Gardener.

Here are the results:

Phosphorus (P) 266 ppm Too Much No remedy needed

Potassium (K) 112 ppm Too Little Remedied with fertilizer

Magnesium (Mg) 103 ppm Just Right No remedy needed

CEC 3.761 meq/100 g Just Okay Will improve with compost

Soil Type: Mineral, Sandy Loam Just Right No remedy needed

Soil pH: 6.7 Just Right No remedy needed

Lime Index : 72 Just Right No remedy needed

Organic Matter: 1.1% Too Little Remedied with compost

  • Apply 3 to 4 lb. Nitrogen per 100 square feet

  • Apply 0 Phosphorus

  • Apply 3.5 lb. Potassium per square feet

  • No lime is needed

  • Organic matter is recommended (compost)

  • Desired fertilizer ratio is 3:0:3

Please note I am simplifying what the results actually look like when they are emailed mostly because I can’t cut and paste it neatly into this posting.

If you are wondering why I am getting this nerdy about my dirt, the reason is pretty simple: I want a beautiful and fruitful garden and if the dirt doesn’t contain the nutrients that all the painstakingly wonderful things I plan on growing need, then I have just wasted a bunch of time and money. Good planning should equal good results.

I’d like to pass on what I learned from Danielle and also the site in each of the categories of testing.

  • Phosphorus is overabundant in Michigan. It’s needed for root development and flowering.

  • Potassium is needed to help plants resist diseases, drought, cold, and heat damage.

  • Magnesium is an essential plant nutrient and plays an important role in photosynthesis

  • Calcium is essential for holding together cell walls and for the uptake of nutrients

  • Cation Exchange Capacity (CEC) – is the ability for the soil to hold cations: potassium, calcium, and magnesium. Danielle described this as the space between particles and after compost is added, there will be less space than what I have now which will be a good thing.

  • Soil Type of sandy loam is actually ideal per Danielle. Too much sand causes water and nutrients to drain quickly away from the roots of plants. Too much clay can hold onto water, salt (dehydrates roots), and can make it difficult for roots to move.

  • Soil pH is the measurement of soil acidity. A soil pH below 7 is acidic and above 7 is alkaline. The goal is to for soil to test close to 7 or just below which is neutral. In general, what I am growing will be happy in a pH of 6.7.

  • Lime is a remedy for soil that is too acidic. Since my pH level is fine, my lime level is fine.

  • Organic matter is where my soil, in its current condition, is abysmally lacking. I will be adding store-bought compost instead of grinding up the leaves in the yard because they’ll consist of too many black walnut tree leaves that contain a nasty substance called “juglone.” Juglone is toxic to many plants. Also, I will probably ask my wonderful neighbors who have horses, if they can spare some dried manure and I’ll add that to the soil as well which will increase the nitrogen level.

Overall, I need to purchase compost and the 3:0:3 fertilizer to be ready when the final thaw comes and I will hire a local farmer to till it into the soil. There are a couple more things Danielle mentioned, that I need to pass on:

  1. Cover the garden soil before winter with mulch. Leaving the soil uncovered allows for weed seeds to blow in. (Well, I’m a little too late for that).

  2. Look into permaculture – it’s one of the most ecological ways to protect soil health

  3. Don’t pull up every bit of dead foliage when the garden is done for the year – its turns into compost and helps the organic matter percentage increase to the 4 to 5% desired level if it isn’t there already.

  4. Use straw at the base of tomatoes plants to cover the soil. Danielle says tomatoes are very susceptible to viruses and diseases from water (rain/sprinkler) splashing soil particles onto parts of the tomato plants. I’ll have to make sure I follow that advice! I have had no luck with my tomatoes in the past and maybe this is why.

I hope this helps any fellow gardeners determine whether a soil test is needed. If you haven’t done one, I strongly suggest it. And next week, I’ll get back into growing plants indoors and share what I learn with that!

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