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1. Q. When should I fertilize my lawn for the fall? Should trees and shrubs be fertilized too? What fertilizer should I use? How much?

A. The important thing to remember is that the fall application of fertilizer IS the most critical. If you were given the option of applying fertilizer only once a year to a lawn, the best choice would be a fall application.

Fall fertilization is applied when shoot growth slows and the necessity for lawn manicuring lengthens from a weekly ritual to an every 10-14 day ordeal. Because of favorable environmental conditions (cool temperatures, short days, and high light intensity) nitrogen fertilizer applied at this time aids the photosynthetic production of carbohydrates. These carbohydrates are stored for use the following growing season, providing earlier spring green-up and an energy source for turf grasses to recuperate from winter adversities.

The best nutrient ratios for fall fertilizer are 3-1-2 and 4-1-2. In the nursery these ratios in fertilizers identified with the name "winterizer". The fall application of fertilizer should take place in as soon as possible. Generally you will need a 40 pound of fertilizer for each 6000 square foot of lawn area. The slow release nitrogen fertilizers are not beneficial in the fall and are not economical to use. In the fall the nitrogen should be available to the grass quickly so that fertilizer elements can be taken into the plant and utilized rapidly while the plant system is still actively growing.

The question of the benefits of fall fertilization for trees, shrubs and groundcovers has been discussed for many years. The benefits of fall fertilization for trees, shrubs and groundcovers has been confirmed by researchers in the field across the nation.

2. Q: When should I fertilize my lawn in the spring and what should I use?

A: The answer is the same nationwide - worldwide. Apply the spring application of a fertilizer containing a slow-release formulation of nitrogen after you have mowed the predominant turf grass in your lawn for the second time. You may mow the winter weeds in your lawn numerous times before the turf grass begins active growth and needs a nutrient application. If you fertilize before the active growth of turf begins you will only be stimulating weed growth. Never use weed-and-feed because of possible damage to ornamentals and feeding before the appropiate time. Apply herbicides separately and specific to the weed to be controlled and the turf grass in which weeds are growing.

3. Q: I need to add iron to my St. Augustine grass. I plan to apply Ironite. When is the best time to make this application?

A: Wait to add a slow-release form of fertilizer such as 19-5-9 until after you have mower the lawn grass for the second time. You may well mow the lawn weeds several times before then but wait until you actually mow the turfgrass you are growing. I would wait until then to apply the ironite too since any iron product may become "tied up" by our alkaline soil conditions.

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