Garden soil PH at 8.6

Asked April 13, 2016, 2:51 PM EDT

Hi- I recently sent a soil sample into the U of M for analysis. pH is 8.6 K is 300+ppm Bray P is 100+ppm Olsen P is 50+ ppm It did not give me a nitrate reading for some reason, but suggested I supplement the vegetable garden with .15 lbs/ 100 sq ft. I took the sample this spring, after having placed wood ash and a lot of cow manure on my garden last fall. I tilled the garden twice prior to sampling. I have two questions- how do I effectively decrease the pH of the garden (1000 Square feet) and still be able to plant and grow vegetables? Secondly, I would have assumed the manure would have brought up the N of the garden effectively. Should I still apply the recommended N? Thanks for your help!

Wright County Minnesota

3 Responses

Do not add more manure or wood ash. The following websites explain why:

Although manure can be a useful soil amendment, most is relatively low in nitrogen. Furthermore, nitrogen leaches readily so supplements are usually needed to maintain levels suitable for optimum plant growth. Add the amount recommended by the soil test.

Go here to learn how to lower the soil pH:

Thanks for the answer. Might copper sulfate work to decrease the pH instead of iron sulfate? The reason I ask is because I have a history of tomato blight and I heard copper sulfate can reduce the risk of tomato blight. thanks!

Copper sulfate is not suitable for use to lower soil pH. Copper fungicide formulations are often used to control plant diseases but these are normally applied to the foliage, not the soil.

More information for your consideration: