Bone meal is coarsely ground bone. Gardeners have utilized ground bone as a nutritional supplement for plants for centuries, and it continues to be very widely used for this purpose. Many garden supply stores stock the meal for gardeners. Historically, this product has also been used as a feeding supplement for animals, although this practice has been brought into question by people who are concerned about food safety. The meal represents a potential vector for bovine spongiform encephalitis and other spongiform diseases, and its use in animal feed has actually been banned in some regions for this reason.
The bones used in bone meal typically come from slaughterhouses and rendering plants. Both conventional and organic bone meal are available, with organic products coming from slaughterhouses which handle organic meat. In addition to basic meal, it is also possible to find bone meals which have been augmented with additional vitamins and minerals. The packaging usually indicates the balance of nutrients in the meal so that gardeners know which product to select for their purposes.
This fertilizer product is high in phosphorus and calcium, among other things. It releases its nutrients slowly as it breaks down in the soil, making it like a natural time-release fertilizer. It is classically used to prepare soil for planting, usually by being raked into the soil or layered into a hole prepared for a transplant. The meal can also be used when establishing bulbs, to provide nutrients to the developing bulb so that it will grow strong and healthy.
Companies produce bone meal in coarse and fine variations. The finer the grind, the faster the meal will break down and release its nutrients. Gardeners can also make their own by crushing and cracking bones and spreading or burying them in the garden. The advantage to supplement is that it is evenly ground and sterilized to remove potential pathogens, and the small grind makes it less appealing to animals.
Bone meal should not be applied to acid loving plants, because it tends to make the soil more alkaline, and it can make these plants unhappy. It should also ideally be mixed with the soil, rather than being heaped on top of it, to encourage dispersal of the nutrients into the soil. This product should be used with other soil amendments such as compost, mulch, peat, and so forth to achieve the right balance of nutrients and the correct soil texture.