Garden Soil Assessment

Every year I do the bare minimum to maintain soil fertility in my garden. I always make a big effort the first year I garden new land, resulting in amazing productivity, then find declining yields thereafter.

This is because I am a skimper. I have come to see that skimping is a pervasive trait of mine. I underestimate in all aspects of my life; ‘oh, that is enough allotted time, money, wood, fabric, food, compost, fertilizer, seeds, what-have-you’. It is very rarely enough.  They say it’s a Scottish thing (aka frugal, but aka cheap).

My garden yields this year were poor. I couldn’t even get my garlic to grow! And so, to be generous (something I am working on) with myself and the land that I care for, it is time that I work on building my soil. I used my new soil test kit (only one step up from my previous kit) to see what major elements might be out of sync. Across various beds I found that pH was acceptable, but low (6.0), N = Trace-Low, P = High, K = High-V.

Great. I need to add N and raise pH. I can do that! But what else? I wanted to know if maybe my soil composition was inferior. I totally geeked out on this very simple test:

Result of the soil 'Shake Test'

Shaken, Not Stirred

Identifying Soil Texture by Measurement

  1. From 6″ down, take soil from several places in your garden to form a composite sample
  2. Spread soil on a newspaper to dry. Remove all rocks, trash, roots, etc. Crush lumps and clods.
  3. Finely pulverize the soil.
  4. Fill a tall, slender jar (like a quart canning jar) 1/4 full of soil.
  5. Add water until the just is 3/4 full
  6. Add a teaspoon of non-foaming dishwasher detergent.
  7. Put on a tight fitting lid and shake hard for 10 to 15 minutes. This shaking breaks apart the soil aggregates and separates the soil into individual mineral particles.
  8. Set the jar where it will not be disturbed for 2-3 days.
  9. Soil particles will settle out according to size. After 1 minute, mark on the jar the depth of the sand.
  10. After 2 hours, mark on the jar the depth of the silt.
  11. When the water clears mark on the jar the clay level. This typically takes 1 to 3 days, but some soils may take weeks.
  12. Estimate the % of sand, silt, and clay.

Next, find your soil type on the triangle plot:

Soil Composition Triangle

Soil Composition Triangle

So my soil type is ‘Sandy Loam’.  Ideal, many garden books would say.  The sand allows good drainage so roots do not rot in saturated soil, and the silt and clay hold moisture and ions that the plants need to grow. I don’t know what it means that my clay content is so low, but I am sure compost can fix most garden problems!

Here are my plans: wood ash to raise pH, animal poop to raise N, and another round of ‘cure-all’ compost

We have been burning a lot of wood this fall (yet to turn on our electric heat) and I was just wondering what to do with my ashes.  I was thinking soap, but the low pH got me thinking about soil amendments!  My garden book says sandy soils require 3-4#/100 sqft, while loam soils require 8#/100 sqft to raise pH by one unit.  I will aim for a 0.5 increase in pH units.  My beds are approximately 50 sqft each, so I will feed my sandy loam soils 2#/bed.

Wood Ash for increasing pH

This 2-gallon bucket of wood ash weighs 5# – enough for 2 of my garden beds

My only concern about the wood ash is raising K further.  I have read that excess K can cause Mg and P deficiency.  Que hacer?

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4 Responses to Garden Soil Assessment

  1. Nancy says:

    I am SO seeing a tow-headed short-haired 8-year old sitting on a big rock at camp with small glass dishes, various organic items and water, and paper-and-pencil. Nice to know that can turn into practical knowledge! Way to go, Jen!

    • jkmcintyre says:

      I didn’t take any pics of my soil test kit – it’s simple, but I totally love putting things in the test tubes, adding reagents, watching things happen! 🙂

  2. shanegenziuk says:

    Great soil test I’m going to try it out. As for frugal, I’ve used tonnes of coffee grounds as a compost ingredient and worm feed. Costs nothing, add nitrogen, and conditions the soil. Good luck for next season!

  3. William says:

    I have to try this. You make it look very easy. I’m on a very tight budget, so any tests are appreciated. I started my garden recently. It’s in the cleaning out the brush before the ground freezes phase. Even though I live in the southeastern part of the United States (Atlanta,Georgia) it does get rather cold at times.Between the leaves,kitchen compost, and other organic improvements to the soil, I hope by the time spring comes around my garden will be ready to go.

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