What Does Bone Meal Mean?
Bone meal is a soil or grow medium amendment that is a mixture of both coarse and finely ground animal bones. Bone meal is mainly made from beef bones, but can be made from the bones of any commonly slaughtered animal.
Bone meal is primarily used as a fertilizer or soil amendment, particularly in organic gardening. It is an excellent source of phosphorus and calcium that is useful during the vegetative stage of plant development. Because it is derived from organic ingredients, bone meal is safe to use on consumable plants like cannabis.
In addition to bone meal, there is blood meal, a quicker release alterative to bone meal.

Maximum Yield Explains Bone Meal
Bone meal is used primarily to provide calcium and phosphorus to plants and soil. Phosphorus helps plants grow and effectively perform photosynthesis, while calcium promotes the formation of healthy plant cells, allowing plants to transport and process other elements throughout their systems.
Bone meal has several different benefits when applied to plants. One benefit is that bone meal takes a longer amount of time than blood meal to break down, which means it releases nutrients slowly. Bone meal should last the entire duration of a plant's growth cycle as it has a slow release of around six months. It does not dissolve in water.
When used in this way, bone meal provides plants with a steady dose of nutrients, rather than a quick burst. Additionally, unlike most chemical fertilizers, bone meal will not leave plants with a fertilizer burn if a gardener inadvertently applies too much.
Like many fertilizers, both organic and chemical, bone meal is dangerous to certain pets, like dogs. For vegans, alternatives to bone meal include kelp meal.
Bone meal is sold in big box stores and local hydroponics stores. Directions for applications will vary from brand to brand. Bone meal can be mixed with the soil or grow medium at the beginning of a growth cycle, or added to a small hole before growing new plants or during transplanting. For plants that are established, half a cup or so of bone meal can be sprinkled over the root zones. This should generally be done in the spring before buds begin to appear.