Sunday, May 6, 2012

Soil test

I bought a soil test from Johanssen's Greenhouse (lusterleaf rapitest). Could have gone with the UW-Extension test, but I didn't feel like taking the time, and for the same price, I get 10 tests with the do-it-yourself kind.

The main reason I wanted to test my soil is that I read that onions prefer a slightly acidic soil of pH 6.0-7.0). My soil, which is actually a combo of soil and compost, tested at 7.0 or higher, probably north of neutral.

The test told me about all the ways I could amend the soil to acidify it by adding iron or aluminum sulfate. But I also want to, within the constraints of my small garden, rotate crops. So one year's onion patch may be next years tomatos, which can tolerate 5.5 - 7.5 or eggplant (5.0-6.0) or peppers (6.0-8.0).

Actually, now that I look at my favorite veggies, all of them prefer a bit more acidic soil. Maybe it is time to amend. 

What are your thoughts on the subject?

1 comment:

  1. Almost all the soil in and around Madison is very alkaline. I'm not sure how accurate these tests are now but several years ago they were considered pretty useless. It looks like this test is basically off the chart alkaline. It could be 7.5 or it could be 8.5. I would recommend springing for the extension test and then amending the whole garden to a compromise pH that will work for all the plants. If you shoot for 6.5 to 7.0 you'll be golden. But, with the highly alkaline soil here it can be difficult to get the soil into that range.