Hi there! I just received my soil test results (V2T9C2) and have a few...

Asked November 16, 2019, 8:13 AM EST

Hi there! I just received my soil test results (V2T9C2) and have a few questions. My phosphorus, potassium, and magnesium are all "above optimum." Does that mean my soil is too rich? My practice is to spread compost after harvest and work it in to the top few inches with a handheld claw. The compost is comprised of rabbit manure, chicken manure, animal bedding (pine shavings or straw), spent plants and grass clippings, and kitchen scraps. I've been gardening at this site for three years. I did not use fertilizer the first two years because it seemed my plants were vigorous and healthy without it. This year, when things seemed slow to start, I side-dressed with a 4-6-3 organic fertilizer one time and also used diluted fish emulsion once. Both were used in accordance with directions on label. Now I see that neither of those were needed! So, back to the question-- does above optimum mean too much? I already applied compost this fall, but for next year, should I skip the animal manure and just work in some shredded leaves for organic matter and nitrogen? Or peat moss to add organic matter and slightly lower pH? Thank you for advising me, Stacy Harrison

Dickinson County Michigan

1 Response

hi Stacy

The above optimal levels mean that there is too much P, K, and Mg in the soil for what is needed by plants. This means that if you add any type of fertilizer that contains these nutrients, it's just a waste of money and the fertilizer ends up flowing to a waterway. Animal manures that you are adding also contain these nutrients, so we don't recommend you add these manures either. In another three years, you can retest to see where the levels are.
Nitrogen, on the other hand, will be needed for plant growth. Please follow the recommendations provided for nitrogen. Always remember to never apply all of the nitrogen at one time as plants cannot use it all at one time, i.e. over the plant's lifespan.
You can apply organic matter such as shredded leaves or your idea of mixing in some peat moss should help with lowering the pH some.