As the growing season progresses, the gardener needs to monitor their plants’ growth. The goal is to provide the basic items the plant needs to remain healthy, and nitrogen may be lacking with the extra rain fall.
A soil test will identify what is in the soil for plants to use, such as phosphorus and potassium levels. Recommendations can be suggested from the soil test. Garden soils are not generally tested for nitrogen. The availability of nitrogen changes continually.
Nitrogen promotes rapid vegetative growth, particularly with grasses. It is a vital element in the formation and function of chlorophyll, which is a key ingredient imparting a dark green color.
Adequate nitrogen also does many invisible import functions. It synthesizes amino acids, which in turn form protein. Nitrogen will regulate the uptake of other nutrients. Nucleic acid and enzymes need nitrogen to fulfill their roles.
Nitrogen is in our air, organic matter, water and soil. The goal is to have the right amount available at the right time for the plant to use. There may be enough naturally or some addition is needed. Each gardener will need to make that decision.
There are three nitrogen-only fertilizers likely available. Urea, ammonium sulfate and blood meal are the ones I can find. All are readily available to the plant by watering them into the root zone after applying.
They vary in concentration of nitrogen. Urea is the most concentrated with slightly over two pounds, equaling a pound of actual nitrogen. It would take slightly over eight pounds of blood meal to make an actual pound of nitrogen. A little less than five pounds of ammonium sulfate are needed.
A publication on top or side dressing nitrogen fertilizer is available at www.riley.ksu.edu or at the Extension office. Now is a good time to add nitrogen to warm-season grasses, annual flowers and several vegetables like sweet corn. Other plants will need it during this growing season.