I found these instructions and they seem to make sense.
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I found other "how to make" fertilize websites. The only thing that I find missing from these fertilizers is iron and sometimes potassium.
I remember the month after the huge fires in souther california ( we had to evacuate). I had the greenest and most lush dark, green grass. Later I found out that pine needles and ash makes great fertilizer. That's what was in the air for about a month.
The grass loved it, our lungs didn't.