Follow these steps to prepare warm-season lawns for the winter:
- Do not apply nitrogen fertilizer at this time. Lime and/or potassium may be applied at this time if a soil test indicates that it is necessary. August 15th is the latest date recommended to apply nitrogen to a warm-season lawn, because nitrogen encourages new growth that is not desirable at this time of year. Potassium has been shown to improve cold tolerance. The good news is no additional fertilizer is necessary IF the lawn has been properly fertilized throughout the growing season. For more information, see HGIC 1201, Fertilizing Lawns.
- Raise the mowing height by ½-inch to promote deep rooting and increased carbohydrate production. For more detailed information, see HGIC 1205, Mowing Lawns.
- Irrigate the lawn with 1-inch of water per week in the absence of rain. After the lawn is dormant, irrigate when needed to prevent desiccation during warm, dry, and windy weather. For more information see, HGIC 1225, Conservative Turfgrass Irrigation and HGIC 1207, Watering Lawns.
- Apply a pre-emergent herbicide to prevent cool-season weeds such as annual bluegrass seeds from germinating. Annual bluegrass seeds germinate when soil temperatures drop below 70 °F. Pre-emergent herbicides can be applied to well-established lawns when air temperatures reach a daytime high of 75 °F for four consecutive days. For more information see, HGIC 2325, Annual Bluegrass Control.
- Keep tree leaves off the lawn. If the lawn is covered with fallen leaves the turf is not able to produce carbohydrates that are necessary for cold tolerance.
- Compacted soil will decrease the lawn’s cold tolerance. Core aeration helps reduce soil compaction. This cannot be done at this time of year, so make plans to core-aerate the lawn next spring after green-up.
For more detailed information on each warm-season turfgrass species see: