Last Fall I purchased a dozen bags of Whitney Farms Alfalfa Meal on sale for $3 per 20 lb bag (thanks Ken A.!). Each bag contains about 30 pints of material. Today I used it for my February feeding.
Cost comparison, per pound of Nitrogen.
Whitney Farms Alfalfa Meal: $3 / (20 lbs x 2%) = $7.50 per lb of Nitrogen.
Spectrum 16-16-16: $8 / (20 lbs x 16%) = $2.50 / lb N.
GroPower Premium Citrus & Avocado Food: $45 / (40 lbs x 8%) ~= $14 / lb N.
Application rate comparison, at 1 lb Nitrogen per year:
Whitney Farms Alfalfa Meal: 30 pints / (20 lbs x 2%) = 75 pints per year (wow).
Spectrum 16-16-16: 1 pint / (1 lb x 16%) = 6.25 pints / yr.
GroPower Premium Citrus & Avocado Food: 1 pint / (1 lb x 8%) = 12.5 pints / yr.
75 pints is 1.25 cubic feet or 2.5 20-lb bags, per tree per year. Essentially it would become a significant fraction of your mulch!
