The basic ingredients used for making balanced organic fertilizers
can vary and what you decide on will largely depend on where you
live. Seed meal usually forms the body of the blend. Seed meals are
high in nitrogen and moderately rich in phosphorus because plants
concentrate most of the phosphorus they collect during their entire
growth cycle into their seeds to serve to give the next generation a
strong start. Seed meals contain low but more than adequate amounts
of potassium.
The first mineral to be removed by leaching is calcium. Adding lime
can make all the difference in wet soils. Dolomite lime also adds
magnesium and is the preferable form of lime to use in a fertilizer
blend on most soils. Gypsum could be substituted for lime in arid
areas where the soils are naturally alkaline but still may benefit
from additional calcium. Kelp meal contains valuable trace minerals.
If I were short of money, first I'd eliminate the kelp meal, then
the phosphate source.
All ingredients going into this formula are measured by volume and
the measurements can be very rough: by sack, by scoop, or by coffee
can. You can keep the ingredients separated and mix fertilizer by
the bucketful as needed or you can dump the contents of half a dozen
assorted sacks out on a concrete sidewalk or driveway and blend them
with a shovel and then store the mixture in garbage cans or even in
the original sacks the ingredients came in.
This is my formula.
4 parts by volume: Any seed meal such as cottonseed meal, soybean
meal, sunflower meal, canola meal, linseed meal, safflower, peanut
meal or coconut meal. Gardeners with deep pocketbooks and
insensitive noses can also fish meal. Gardeners without vegetarian
scruples may use meat meal, tankage, leather dust, feather meal or
other slaughterhouse waste.