We recently had our soil tested by the University soil testing service. They found our pH to be 7.8 - alkaline. They give a recommendation for fertilizing of 2 lbs/1000 sq ft of Nitrogen / 0.5 lbs/1000 sq ft of Phosphate / 2 lbs/1000 sq ft Potash TOTAL per year (the way I read the recommendation). Will following this recommendation bring our alkalinity down over time? if so, how much time to bring alkalinity to Optimum?
Scott County Minnesota
Thank you for your question. The recommendations given to you from your soil test will not appreciably change the soil pH. I am puzzled by the recommendation for phosphate. Typically, Minnesota soils have adequate phosphate levels. I am wondering if you are starting a new garden? I am also curious about any recommendations about the addition of organic material to your soil. Perhaps if you wish to continue this discussion, you could send me a copy of the soil test results?
Recognize that lowering soil pH is not something that will occur quickly. It may take a few years.
For the immediate time, I would suggest two steps.
1). After harvesting things from your garden – assuming that is the soil that you had tested – incorporate large amounts of peat moss into the soil. Dig/till this in thoroughly. This may not be possible if you are talking about your yard.
2). Apply ammonium sulfate or aluminum sulfate (this may be hard to find) to the soil.
You should continue this through 2019. Then in 2020, have your soil tested again. The pH should have dropped.
Also take a look at:
Steve, thank your for your reply. Actually, the soil test(s) were from our lawn. We had soil from both the front yard and the back yard tested - and they are almost identical. We live in Shakopee. We have a lawn service (L.C.S. Lawn Service) who uses "organic" fertilizer. We have an irrigation system and use a "mulching" blade on the lawn mower, returning the clippings to the lawn for most of the year.
I have attached a copy of soil test "image1" - hopefully you can read it!
Using peat moss to lower the pH of your yards may not be a feasible approach. The following site gives you some information about optimal pH for various grasses. However while on the alkaline side, your yard pH may still be acceptable.
Organic fertilizers are generally "slow release" in that their nutrients are released over a period of several weeks. I would suspect that your most of your fertilizer applications have consisted of granules. This is typical for most organic fertilizers.
Without knowing the nitrogen, phosphorous, and potassium amounts in the organic fertilizer, it is difficult to know if the applied organic fertilizer satisfies the soil test recommendations. Your should be able to get this information from the lawn service. Also you might ask your lawn service if they have any recommendation for lowering the soil pH. If you have not had your yards aerated within the past five years, you may want to consider doing this within the next month or so. Sometimes just this rather simple procedure can lower the pH. The mulching blade is a great idea. If you have not done so in the past, consider doing this for any leaves that may fall on your yard.
Thanks for the soil test results.