Preparing Your Lawn for Winter
All of our warm season lawngrass species go into some degree of “dormancy” during the winter months. This means that they slow their growth down and may or may not stay green. This is a natural cycle, regardless of where you live in the state. In north and even central Florida, lawn may stay green or may turn brown, either of which can be normal. Even in south Florida, lawns do not grow as quickly (less mowing required!) in the winter, even though they may remain green. Regardless of where you are in the state, you should work to keep your lawn as healthy as possible through your mowing, irrigating, and fertilizing practices. For more information on how to properly manage your lawn, please refer to EDIS publication ENH979, Homeowner Best Management Practices for the Home Lawn (http://edis.ifas.ufl.edu/ep236).
Lawns in south Florida are typically fertilized year-round with no problems. However, central and north Florida lawns should not be fertilized after mid to late September. The last fertilization should be done with a fertilizer high in potassium (the 3rd number on the bag) relative to nitrogen (the first number on the bag), such as 15-0-15 or something with equal or higher potassium to nitrogen. This helps to impart some stress tolerance to cold or freezing temperatures and may enhance spring greenup. In central Florida, do not fertilize lawns between October and the end of March. In north Florida, avoid fertilizing from mid-September through mid-April. Keep mowing height high year-round (3.5 to 4” for most St. Augustinegrass cultivars and bahiagrass and 2 to 2.5” for centipedegrass and coarse-textured zoysiagrass lawns) for additional enhanced stress tolerance.
Coming Out of the Freeze
Freezing temperatures will turn lawns brown. Do not panic, this is a normal part of winter dormancy. When the days become longer and temperatures start to warm up in the spring, the growing points will become active, bringing green growth to the lawn again. Do not fertilize your lawn in the winter to try to green it up after a freeze – wait for the natural cycle of events to occur in the springtime. Fertilizing after a freeze will do more harm to your lawn than waiting for spring greenup. Do not apply a weed and feed product for preemergence weed control during the winter in central and north Florida. Lawns generally do not require as much irrigation during winter months, so scale back your irrigation systems. In central Florida, you may need to irrigate weekly or every other week, while in north Florida, it may be every 3 to 4 weeks. You will not need to mow for some time; when you do need to mow again, be sure to cut at the highest recommended height for your grass type. Do not scalp the lawn, as this makes it less able torecover from freeze damage.
How can you tell if your grass has truly succumbed to a winter freeze or if it is only dormant?
One way is to cut small plugs of the grass (with roots and shoots attached) and plant them in a pot, put it in a warm spot with natural sunlight and see if the grass regrows. If your lawn does not recover come springtime, remove the decayed vegetation from the affected areas and replace with either sod pieces or plugs. Do this before weeds have a chance to germinate and take hold of the ground. It is possible that not all of your lawn will be affected, perhaps just those areas that are most exposed to the cold temperatures. Following these tips will help your lawn survive freezing temperatures. For more lawn care tips, go to http://www.yourfloridalawn.ifas.ufl.edu/.
This information was prepared by L.E. Trenholm, Associate Professor, Environmental Horticulture and
J.B. Unruh, Associate Professor, West Florida Research and Education Center
