Fall Biology
Most noticeable this time of the year is the lawn is not growing as fast and needs less mowing. This is the beginning of the fall transition.
Summer sun, heat, and rains are yielding to cooler mornings, shorter days and less rain. This is a transitional period for your lawn – transitioning from full-throttle metabolism of the summer to restful idling as the turf retools the metabolic engine for the colder winter months.
It is also the time for the final burst of growth of weedy summer annuals. Taking advantage of the slowed growth rate of the St Augustine, the weedy species try to gain a toehold on some real estate in the lawn.
Your Lawn is Not Dying
Expect your lawn to have more brown leaves than green. This causes the "browning effect' of your lawn in the fall. Some people describe it as "dying" or "brown" or "doesn't look as good as it did last month". This is a natural reaction to seeing more brown leaves than green leaves. Soon there will be more green leaves than brown again and the lawn will appear healthy and green.
Fall Fertilization and Insect Control Plan
The primary focus is on strengthening the turf. Summer growth rates have provided for excess metabolites that need to be stored. Yet the excess sugars and slowed metabolism make the turf a target of insects and disease and recovery from attacks is reduced. My fall plan is to increase potassium – an organic fungicide – maintain micronutrients and nitrogen levels and continue with insect protection until the cooler months.
Weed Control
As the average daytime temperatures drop, weed control can be aggressive without fear of damaging the turf. The plant metabolism slows fall through spring and the impact of herbicides on the turf is reduced. This allows for aggressive applications of herbicides The strategy: Hammer the weeds all winter long so the lawn is as “clean” as possible in the spring.
Watering and Mowing
Normal mowing as high as the mower will go is the best for your lawn in the fall. Do not be tempted to lower the mowing height for any reason – this only damages your lawn when it is less likely to recover from stress.
Continue to water as often as law permits. The determining factor for watering is not the weather but the soil – our sandy soils in Pinellas can only hold enough moisture to sustain your lawn for 72 hours max! Therefore, be sure to give your lawn a drink of water at least every 72 hours.
Turf Tip: Reducing water does not “harden off” the lawn or “force roots deeper”. Reducing water stresses and weakens the turf, eventually destroying your lawn.
