From MGH by Ed Rosenthal: Growers who make their own nutrient mixes based on parts per million of nutrient generally use the following formulas:

germ - 15 to 20 days: N 110-150 P 70-100 K 50-75
Fast Growth: N200-250, P60-80, K 150-200
Pre-Flowering: N70-100, P 100-150, K 75-100
Flowering: N 0-50, P100-150, K 50-75
Seeding - fertilized flowers: N100-200, P 70-100, K 100-150

Organic growers can make "teas" from organic nutrients by soaking them in water. Manures and blood meal are among the most popular organic teas.

Bloodmeal NPK is 15-1.3-.7 and releases nutrients easily.

From LolaGal: Hope this helps some, couldn't find the directions on how much per gallon, I would guess 1 TBsp per gallon if you don't use the PPM chart above.