blueberry bed soil all screwed up

Asked March 29, 2018, 10:00 AM EDT

Hi there, I've got a few 12" high raised beds I created last summer in which I have just recently planted 6 small bare root blueberry plants. I had the soil beneath the beds tested last summer, and found that my pH was 5.2, P = 6, K = 46, Mg = 74, and Ca=40. My % organic matter was only 1.6 (it's basically clay). So, to raise my organic matter and other nutrients, I tilled into my clay soil a 50:50 mixture of topsoil and leaf compost, a lot of peat moss, and then I mulched it with pine needles and let it sit over the fall and winter. After planting the bare-root blueberries, I sent off a sample of the bed soil for analysis just to be sure It's good for blueberries. I just received my results and they're terrible! My pH is now 7.8, P = 290, K = 508, Mg = 284, Ca = 179. Organic matter is now 9.8% though. How should I fix the soil? What should I do with my blueberries in the mean time?

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1 Response

That pH result must have been a shock. Probably the soil in the soil/compost mix was extremely high. That is not an unknown problem. You could contact the soil provider and ask about the pH. One consolation is that organic matter has been known to buffer the high pH and you have plenty of organic matter..

At any rate, since blueberries like a low pH, you can lower it with sulfur, then iron sulphate. Our webpages on blueberries includes instructions for doing this: https://extension.umd.edu/hgic/blueberries-selection-and-planting
You might want to look over the other blueberry info.

Next year, test your soil again to see where it stands.

ECN