Blood meal is a nitrogen amendment, which is essential for raising the nitrogen levels in spent soils- giving plants the nutrients they need to grow. Often, you need to apply blood meal to vegetable gardens and annual flower beds, where consistent planting can drain the nitrogen from the soil. Nitrogen encourages plants to grow more lush and green.
It is entirely organic, made only of animal blood. Do not apply directly around plants, as this can burn them. Also helps acidify basic soils.