The 3 major nutrients which may be lacking in grasses are Nitrogen (N), Phosphorus (P) and Potassium (K).

Nitrogen (N):

Grasses require a greater amount of nitrogen because it helps produce a healthy green plant. However, too much nitrogen can cause quick blade growth at the expense of a strong root development. The best type of nitrogen for your lawn is slow-release, because it offers a consistent supply of N and has less chance of burning the grass or leaching into the soil.

Phosphorus (P):

This nutrient helps roots and seedlings develop more rapidly and improves winter hardiness, which is important for lawns planted in the fall. Phosphorus also increases water use efficiency and makes your lawn more drought tolerant.

Potassium (K):

Acting like a vitamin, potassium helps strengthen the grass plant. It also works to make your lawn more disease resistant and hardy.