There’s no way to know whether your soil needs phosphorous or potassium without doing a soil test. If you don’t want to bother and milorganite is giving good results, I’d just stick with that.

i am not trying to be cheap, and understand that it is the only real way to tell the npk, but my extention office wanted $40 to run a test. Is that reasonable ?

Ive used milorganite only because it was "safer" to use with me not knowing much, not because it worked very well. I am afraid because i have sandy sandy soil that all that slow acting fertilizer is being drawn through the sand so fast that its not really doing anything. That's why i was interested in the fast acting 10-10-10.

Most people online use Logan Labs, which is $25 for a test. Test at 4” and someone here can give you suggestions. You’ll also find out how well your soil holds on to nutrients

awesome, thanks a lot !!

If you have sandy soil, your probably going to need some potassium. The numbers should look more like: 10-5-20