Hey people, there is a formula for figuring how much nitrogen is in a bag plus how much that bag will cover. Example 15-0-5 = .15 x 50lb bag = 7.5lbs of nitrogen in that 50lb bag. For some reason I can't remember the rest of the formula. Saw is a couple of weeks ago, wrote it down and the little misses seemed to eat it up. Actually, I think it tells you how much the bag covers. thanks people.