| Nutrient / Application |
Function |
Symptoms of Deficiency |
Symptoms of Excess |
Nitrogen (N)
San Diego soils contain little and it depletes rapidly. Mix into soil before planting or apply to surface and water in. Replenish regularly. Nitrate form is very mobile in soil. |
Important for many growth and development processes. A constituent of proteins, enzymes, and chlorophyll (needed for photosynthesis).
|
Slow growth, stunting, and yellow-green color; more pronounced in older tissue; tips and margins turn brown; premature death |
Excessive vegetative growth, dark green color, excessive transpiration, reduced yield; delayed maturity; few fruits. |
Phosphorus (P)
Does not move far in soil. Remains near source of application. Mix into soil before planting. Apply around the root zone of established plants |
Stimulates early growth and root formation;
promotes seed, fruit, and flower formation
|
Slow growth, stunting, and purplish color on foliage or dark green color; dying leaf tips; delayed maturity; poor fruit or seed development |
Excess can interfere with micronutrient absorption; may mimic Zinc (Zn) deficiency. Click here to go to description of Zn deficiency. |
Potassium (K)
Does not move far in soil. Remains near source of application
Apply around the root zone of established plants. Adequate in most San Diego soils. |
Proper growth of fruits and flowers, ensuring
good size, color
and quantity.
|
Slow growth; leaf tip and marginal burn (starts on more mature leaves); weak stalks; small fruit and shriveled seeds. |
Light green foliage; tendency for Calcium and Magnesium symptoms to appear. |
| Calcium (Ca |
Essential part of cell wall structure, must be present for formation of new cells. Adequate in most San Diego soils.
|
Reduced terminal growth of shoots (buds) and roots, resulting in plant death. |
Interferes with micronutrient availability. |
| Magnesium (Mg) |
Essential for photosynthesis |
Leaves curl upward along margins; marginal yellowing with green “Christmas tree” pattern along mid-ribs of leaves. |
Interferes with Calcium uptake |
| Sulfur (S) |
Responsible for characteristic odors of plants such as garlic and onion
|
Reduced growth, delayed maturity. Light green to yellowish foliage on leaves; small spindly plants. |
Not known |