Testing the Soil

I thought that by going organic and supplementing the soil in the garden with my compost, I would get the right balance of nutrients.  Other organic gardeners have told me they've stopped testing.  But I have spots where some things look pretty anemic.  So I recently bought a soil testing kit and today I finally did the first sample.

The green top is the PH test.  That was the easiest match.  Clearly a 7.  The red was nitrogen and that seems to be low.  The phosphorus is a little harder to tell, probably between medium and low.  And the potassium appears to be medium. (You have to look through the water with the black square on the other side.)  Obviously, testing this way is NOT an exact science. 

An ADN story two years ago says that home soil test kits are inaccurate.

The home test kits for nitrogen, phosphorus and potassium didn't work either. In some cases it was impossible to match the color of the sample to a color on the chart of the soil test package. In others, the readings didn't coincide with the results from the lab and tested high when the lab indicated nutrients to be low.

But I can do 12 tests for about $12.  If you send it for a test, it's about $40 for one.  

They want you to mix soil from all over the yard into one sample. 

To collect a representative sample for an average-size garden, I suggest taking at least five sub-samples. For vegetables and flowers, dig a hole 8 inches deep and, from the side of the hole, take a sliver of soil and put it into a bag. Do this in five locations and shake up the soil to mix it thoroughly.

I know that the soil varies from place to place in our yard.  So I can take soil from different beds and get readings for that bed.  We have some young friends I'm going to enlist to help do some of the other readings.  I think we'll have a good time.  

Even if they turn out to be inaccurate, I'm not a competitive gardener (as any of my neighbors will attest) so I can't do any real damage by adding too much nitrogen.  And putting the water, the tablets, and the soil into the water and waiting for the colors to show up is fun.