http://en.wikipedia.org/wiki/Blood_meal
Blood meal can burn.

Also, your plants are going to need a nutrient solution that has an array of essential main nutrients aswell as trace minerals, that play a vital role in those nutrients being delivered to the plant. So, find one Essentially, miracle grow has all those things, but, you want it in a less potent version, NOT miracle grow. k. thx. if u need tips on nutes, ask that question.