There is no really good way to know how much Nitrogen is too much because it depends on how active a Soil Food Web you have, the soils moisture level, and how available the Nitrogen is, and the N in blood meal is very available. Sprinkling a very little, just enough to make the area smell, blood meal over your mulches may mean something less than you spread around would be available to the plants, bacteria in that mulch would use it to digest the mulch, but that too depends on how much moisture is put down after application since a little too much could wash that blood meal into the soil. A little too much Nitrogen in the soil, available to the plants,would cause lush, green growth that is much more attractive to many insect pests. Probably a much better way to keep the rabits put of the planting beds is to put good, tight fences in place. While the initial expense is higher than some blood meal over time those fences are much less expensive long term, and more effective.

Blood meal works for awhile, but it's very high in nitrogen, so you really don't want to apply it to perennials. Fill a plastic container, such as an old butter tub, w/ bloodmeal, poke holes in the top, and place them next to the plants you want to protect. I've had the deer actually paw at the containers before in a snit. Using a spray product like Liquid Fence is easier and more effective. Also, Milorganite as mentioned can work, but for me, it only works at the start of the season. Once it gets hot, it seems to lose its deer repellant properties. Good luck. They are maddening creatures.

Years ago at our cabin on a Minnesota lake I added blood meal to the holes when planting a bunch of perennials. Raccoons dug up every one of them looking for something to eat.

I have used blood meal for years. I tried to follow this thread in its entirety and thought I had a few things I could add. I noticed that using it to replace manure was mentioned. It is not a replacement for manure, but it sure does help when there is not enough manure. Manure and compost have the wonderful qualities of making the soil moisture just right. There is nothing to replace compost or manure except other compost or manure. I also live in a rural area and never had a buzzard show up for dinner just because I threw out a little blood meal. I do have pets though, and they all prefer fish emulsion over blood meal any day. Gee, anybody got any thoughts on why? If you can keep the pets out of the fish emulsion,it is the most perfect replacement supplement that I have found for manure and compost, but it is not a perfect replacement either. I have used blood meal in small quantities, large quantities and everything in between. I have never burned a plant root with it, and I am not sure why. I cannot burn plants with rabbit manure either. That is called a cold manure. Goats and sheep, I am told, also produce cold manures. It means that although they produce nitrogen in abundance, the jillions of creepy crawly things that break down the soil do it somehow differently that other livestock manures. I have certainly burned roots with chicken manure. Rabbit manure has more nitrogen than all of the common live stock manures found in North America, and I do not know any animal that produces more nitrogen in its manure than rabbits. I love the stuff, but we are not talking about rabbit manure. We are talking about blood meal which I also love. Also liquid blood meal was mentioned. Really? Couldn't you just do your own slaughtering? I do not know anybody that sells it that way and don't think I would buy it if I did. If you want to pour a store bought nitrogen rich liquid over a spot, use the fish emulsion that I just mentioned in a paragraph above. Just develop a good plan for keeping pets out of it. I don't have any because I do not wish to spend the money on other products that repel them. Those also exist. Just ask for them wherever you buy garden supplies. Let me add this about nitrogen's side effects. Nitrogen does indeed promote lush green foliage that may not be desirable if one really wants bigger fruit than plant, but I have to add that bigger plants produce bigger fruit. I grow watermelons on land that I inherited from my father. When I told my mother that I planned to do that, she was quick to remind me that my father never could grow watermelons on that land. (He would not listen to good advice because he thought he knew everything.) There were several reasons for that, but we are just talking about fruit size. His watermelons and at first mine were far too small, baseball or softball size, and part of the reason was because I did not know how to time watering or fertilization and such. Watermelons need the most nitrogen while the vines are forming and before the fruit forms. Then while fruit is forming, they need to receive the most phosphorus and potassium. However, this is not advisable if nitrogen has not been applied aggressively enough. Even as I write this I have watermelon flowers, but still have to apply nitrogen to get all of my melons on the same page. They are growing at different rates because they popped out of the ground on different days, and I replanted about a week after the first planting, and the second planting also popped out of the ground on different days. I also plan to sell them. So I have them in many stages. Some only have their dicotyledon leaves while others have long vines, but I am not satisfied with any of their growth rates because I know from experience that at present they are only long enough to produce baseball and softball sized watermelons. Therefore I am making amendments with Organic Miracle Gro Liquid plant food that has 8-0-0 and is made from sugar beets. If the smallest plants I have right now started making fruit at their present size, they probably wouldn't have anything bigger than marbles. I am sure that all of this applies to all fruit and vegetables. Bigger plants make bigger produce, but more phosphorus and potassium applied at the right times make more fruits and vegetables. I hope this has been informative. Grow something really grand.