Our trees and vines are flowering and lawns are starting to green up naturally, but one glance at the calendar and it is still early spring. The last official frost date for the Florida panhandle can be into April depending on location. We know our day time and night time temperatures are still fluctuating every other day. We also know the stores and nurseries are stocked with shelves and pallets of fertilizer. So the big question is when can I fertilizer my lawn?
My answer after years of practice is always it depends, but my non-scientific rule of thumb to homeowners is wait until you mow three weeks in a row and make sure you’re past the last frost dates for your area. If you need to mow three weeks in a row for height, then your lawn is actively growing and most likely we are into a temperature range good for fertilizer applications. If you apply fertilizer to a lawn that is dormant, the fertilizer will not be taken up by your roots and it can leach below the root zone wasting money while not improving the lawn and possibly causing environmental concerns.
With that said, there are some factors to consider. We always recommend doing a soil test first. This can be done in advance of spring. Your test results might indicate having sufficient nutrients in the soil, so not applying would save you money and the lawn would still look good. The soil test will also indicate what nutrients are in excess or lacking, then you can apply only the nutrients needed.
I have found that fertilizer is still very much misunderstood. When I ask homeowners whether they consider fertilizer to be medicine or a stressor, most will answer medicine and we all know if a little medicine is good, then a bit more is better. However, it is more accurate to think of fertilizer as a chemical stressor. If my lawn is unhealthy, then I force my lawn to grow and it can further weaken my plants. Think of it like this, if you’re not feeling well at night before you go to bed, should you consume one of those big energy drinks? Not if you want to sleep and hopefully feel better in the morning. Apply fertilizer when the lawn is ready and capable of having a positive response when spring fully arrives.
Here are some items you should know before you fertilize the lawn. Fertilizers used in Florida should have a license number that begins with F followed by a series of numbers. It is important to check your fertilizers before you apply. You need to know what type of turfgrass you have in your lawn. We have a lot of bahiagrass and centipedegrass lawns in the panhandle. Each will require a different regiment. You are only allowed to apply one pound of nitrogen per 1,000 square feet per application and you should never apply more than the recommended rate. I always refer to a childhood fable “The Tortoise and the Hare” when thinking about plant health. Slow and steady makes for a better lawn in the long run. This means you need to measure your lawn, understand how to calculate the nitrogen and then apply correctly with the right equipment and spreader patterns. We also recommend very little phosphorus (the middle number on the fertilizer bag 15-0-15) for Florida lawns. Our soils are usually sufficient and this is another item your soil test results will confirm.
Remember, your local Extension office is always here to help especially making sure you treat the lawn right. Think before you apply because your long-term goal is improving the lawn quality.
The Florida Fertilizer Label (https://edis.ifas.ufl.edu/ss170) and General Recommendations for Fertilization of Turfgrasses on Florida Soils (https://edis.ifas.ufl.edu/lh014). T. W. Shaddox, assistant professor; UF/IFAS Fort Lauderdale Research and Education Center, Ft. Lauderdale, FL 33314
Homeowner Best Management Practices for the Home Lawn (https://edis.ifas.ufl.edu/ep236). Laurie E. Trenholm, professor, Extension turfgrass specialist, Environmental Horticulture Department; UF/IFAS Extension, Gainesville, FL 32611.
Bahiagrass for Florida Lawns (https://edis.ifas.ufl.edu/lh006). L. E. Trenholm, professor, turfgrass specialist, Department of Environmental Horticulture; J. B. Unruh, professor, turfgrass specialist, UF/IFAS West Florida Research and Education Center; and J. L. Cisar, retired professor, turfgrass specialist, UF/IFAS Ft. Lauderdale REC; UF/IFAS Extension, Gainesville, FL 32611.
Centipedegrass for Florida Lawns (https://edis.ifas.ufl.edu/lh009). J. B. Unruh, professor, turfgrass specialist, UF/IFAS West Florida Research and Education Center; L. E. Trenholm, associate professor, turfgrass specialist, Environmental Horticulture Department; and J. L. Cisar, professor, turfgrass specialist, UF/IFAS Ft. Lauderdale REC; UF/IFAS Extension, Gainesville, FL 32611.