Potassium and brussel sprouts.

Thank you for your question. Without a soil test determining what nutrients you need to supply is like driving with a blindfold. Adding the wrong nutrients can affect the uptake of other nutrients. You can get a soil test through MSU (http://homesoiltest.msu.edu/). Your soil can tell you a little about potassium levels. If you have sandy/well drained soils you may have low potassium levels since potassium can leach out of soils. Although not the best option a balanced fertilizer 10-10-10 can be used if there is no test available.

I hope this helps,