Thursday, April 1, 2010

Soil Testing

I'm no soil expert, but I do know that your soil's pH should not be too high, nor too low. A nice, neutral number is best. I had no idea what my soil's pH was, so I went out and bought myself a soil testing kit. The kit not only included the pH test, but also tests for plant foods, such as nitrogen, phosphorus and potash. I'm not certain if this kit actually tests for the presence of plant foods, but I did all four anyway. Here are my results. Perhaps, someone knows more than I do and would like to share with me the reasons for testing for 'plant foods,' such as potash. Mostly, I was in it for the pH test.

The instructions for the kit, made by a company called McKenzie (based in Brandon, MB), directed me to dig 4" into the soil where my proposed garden would be and put into a sealable container. I used a 500 mL Mason jar, filling it with one part soil (50ml) and 4 parts water (200 mL). I should the jar vigourously for one minute, as directed, and then let it sit for 10 minutes. After the sediment had settled, what remained was a mirky fluid. I carefully transferred the amount instructed into the little vials provided, except for the pH test. Each vial was colour coded and contained a matching capsule with powder in it.

Carefully, I separated the capsule ends and emptied its contents into the corresponding vial. I shook each vigourously and let rest for one minute. After the minute had passed, I held each vial up in the sunfilled room (but not direct sunlight) and compared its colour to the one on the chart provided. This is the hard part. In different light, the colours changed depth, at least to my eyes. I have included pictures of the vials below for your evaluation.
The results for Nitrogen were normal; the colour best matched the one on that chart described as 'medium'. As far as my eye can see, the Phosphorus test came back 'very low'. The Potash test was, perhaps, the most difficult to read. Although the liquid itself was very pale orange, the soil changed to a deep orange colour. Based on the colour of the water, however, the results read 'low' to 'very low'.
Next, I tested the pH of the soil. For this test I merely took some of the same soil, dug from 4" below the surface, and and put it directly into the vial provided, to the first line. The I added the contents of the capsule provided and water to the 4th line. Much like the other tests, I should the vial vigourously for about 1 minute, and then let it rest for 10. The results came back a dark green which means that the soil's pH is somewhere between 7-8. With 7 being neutral, 8 is slightly alkaline. I have included a picture of the sample for your evaluation, as well. If anyone has more information to add to this that will help me in my gardening adventure, please feel free to post a message. This is a learning experience for me and, as I said before, I'm no soil expert.

1 comment:

  1. Hi Mel,

    A pH of 8 is pretty high and reflective of the limestone base of the soils in our area - the soils on our farm are also in that range. Our ground waters tend to be high in pH as well for the same reason. Usually these soils are high in calcium, which is good, but the high pH can cause problems for the availability of some nutrients, such as iron and phosphorus.