2.1lbs of n per 1000 is too much spring nitrogen
another 2.8 lbs of N per 1000 in fall
How much n, p, k from 5-2-4 sustane is unknow since application rate not given
Appears your program doesn't provide enough p and k!!!!!! Maybe none if you omit the sustane summer application!!!
A lot of people consider something an organic only if it comes from something once living!!!!
Yes, something that is mined and not altered by man is considered a natural product!
AND YES, the OMRI, organic material review institute, does give 5-2-4 from sustane the stamp of approval, even though it contains sulfate of potash, ( not an organic), feather meal, and turkey litter!
This forum as never definned organic fertilizer, or a natural fertilizer!!!
A lot of fertilizer products mined are altered by man, usually to make them more readily available!!!!
In closing, I usually would accept sulphate of potash in a natural organic fertilizer program.
Timothy J Murphy Specializing in Quality Turf
Bs in Plant and Soil Science
Almost 40 yrs exp., 20 as GC superintendent
Primarly work with cool season turf