While both sound very similarly and can be easily mixed up, they are differ quite a bit from each other.
Blood Meal is a by product of slaughter Houses hence the blood part. It is dried and made into a powder. It is high in nitrogen and an excellent natural way to fertilize your organic garden. It is also known to deter other animals from your veggies.
Bone Meal is another by product of a slaughter house. The bones are ground up finely to make a granulate or powder. This is more of a slow release fertilizer and is not as readily available as the Nitrogen in Blood meal is. It supplies the plant with phosphorous and proteins. Although it will contain some nitrogen, the amount is not sufficient for the proper growth of a plant.
