Blood Meal (13-0-0) Fastest release time of any organic nitrogen source. It usually comes from cattle or hogs as a slaughterhouse by-product. Side-dress 3 weeks after transplanting or 4 weeks after seeding or till into soil. As a dressing, apply at ¾#/100 row ft 3 weeks after transplanting or 4 weeks after seeding, or till into soil at 3–5#/100 sq ft.