As the chill of winter leaves us, it’s tempting to head outside for a dose of fresh air and sunshine. If the springtime pollen doesn’t chase you back inside, you may notice that grasses are just beginning to turn green again. Surely it’s time to give them a head start with some fertilizer, right?
Not necessarily!
The warm-season perennial turfgrasses in our area survive the cold of winter by going dormant. As temperatures drop in the fall, they shut down their growth, turn brown, and wait until conditions are more favorable. As the weather warms again and days grow longer, these grasses, which include centipede, St. Augustine, and zoysia, use internally stored nutrients to recover from their ‘hibernation’. They won’t be actively taking up nutrients from the soil until they’ve had a chance to increase the size of their roots. Add fertilizer to a lawn too soon and much of it will be lost as it leaches through the soil. Nutrients that are lost to leaching end up in our streams, rivers, and in the Gulf, where they can cause the rapid growth of algae and other organisms, which can unbalance ecosystems and harm the environment.
When is the right time to fertilize? In North Florida, it’s usually not until the middle of April that conditions are best. This can vary year to year, but the significant possibility of a cold snap in March makes April more likely as the correct time. Be aware that newly planted turf, including sod, does not need to be fertilized immediately. Wait a month or two before fertilizing newly established turf.
It’s good to be cautious about ‘weed-and-feed’ products this time of year, as well. These are mixtures of fertilizer and herbicides, but the climate in North Florida makes timing of application impossible. These products may contain preemergent or postemergent herbicides. Preemergent herbicides are applied just before weed seeds germinate, killing the seeds as soon as they begin growing. Postemergent herbicides, on the other hand, are applied to weeds that are already up and growing. Preemergents are applied when the weather has begun to warm up, just before temperatures have reached 65 to 70°F for four or five days in a row. Postemergents are applied while weeds are still young.
In this area, if a weed-and-feed product is applied at the right time for an herbicide to work, the timing will be wrong for the fertilizer portion of the product to be effective! You may end up fertilizing weeds instead of your lawn.
When it is time to apply fertilizer, how much is appropriate? The best way to determine this is by getting your soil tested. A soil test will tell you the pH of your soil, measure the amount of plant nutrients present, and give recommendations on how much lime and fertilizer to apply. Contact your local Extension office for help with soil testing, or see our online publication here: https://ask.ifas.ufl.edu/publication/SS494
For more information on caring for a lawn, try these publications as well:
Weed Management Guide for Florida Lawns
Evan Anderson
Walton County Horticulture Agent
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