Nitrogen

Nitrogen is absorbed by the plants in the greatest quantity. It is necessary for rapid growth and promotes deep green leaves and stems. Nitrogen will not fix itself to the soil, and if unused by the plants, will percolate past the root zone with watering and rains, and must continually be replaced.

Phosphorus

Phosphorus is essential in all phases of plant growth, but is particularly associated with early maturity, the formation of seeds and fruit, increased root growth, and disease resistance.

Phosphorus stays in the soil until it is used by the plant, usually requiring fewer applications than nitrogen, and its effectiveness is enhanced by adding organic matter.

Additional phosphorus is recommended for early season plantings, as availability is lowest in cool weather.

Potassium

Plants take large amounts of this nutrient, almost as much in some cases as nitrogen. It contributes to the overall vigor of the plant, building strong stems and leaves, helping to overcome the effect of heavy foot traffic or adverse weather.

Potassium levels in many intermountain area soils are naturally high, but become depleted as plants use it, and in heavily irrigated areas, such as lawns and gardens.