Winter irrigation protocols

This subject has come up frequently during the past week, so I think it’s worth revisiting the rules of irrigation as we prepare for what passes for winter along the Texas Gulf Coast. 

While we don’t really need to do anything to lawns from a fertilizer or fungicide perspective, our grass still needs water over the next few months.

Here are two examples of recent questions in my email: “With the weather cooling and days being shorter, my lawn no longer needs water, right?” (Nick G., The Woodlands) And “What is your recommendation for watering the grass during the winter months?”  (Sara E., Cypress)  

If you want your lawn to stay healthy and respond quickly at the first whiff of spring, you’ll need to heed my winter irrigation advice.  As in many situations, there’s not a one-size-fits-all answer, but I can supply some general rules.

It’s important to remember that to keep turf, trees, perennials and shrubs healthy year-round, we must continue watering through the winter. With the rain that normally comes during the period, we won’t have to water as much. But roots and even dormant plants will continue to need moisture.

First, I’ll assume that you weren’t bone-headed enough to put out winter rye. Because if you did, to keep it green and thriving for the next three months, it’s likely going to require a lot of irrigation. And fertilizing. And mowing!  Plus, if you don’t sow winter rye perfectly, it turns out to look like the equivalent of a balding man's comb-over! He may think it looks great, but everyone else knows something not quite right.

If you let your St. Augustine, Bermuda or Zoysia grass go dormant (as you should), here are some basics for the winter months:

  • When temperatures are normal, turf needs 1-1 ½ inches of water per week, but in the winter, it can survive on 1-1 ½ inches every 2 to 3 weeks.
  • Yes, Mother Nature’s rains on their own can provide that 1-1 ½ inches over 2-3 weeks in the winter.
  • Root systems are still very much alive, hence the need for moisture.
  • Two months of no rain or irrigation can kill a lawn.
  • Too much moisture when temperatures are between 80 and 60 degrees can lead to brownpatch.
  • If you turn your irrigation system off in the winter in anticipation of freezing nights, remember to turn it back on during warmer days, especially if it’s been over two weeks since a significant rain.
  • If a freeze advisory is issued, run your irrigation a day before it is expected to hit to fortify plants and flowers. It takes longer for well-watered plants to freeze. Also, be sure to protect back-flow valves on the night of a freeze.
  • Winter is a great time to have your irrigation system checked for leaks and potential problems.

If you follow this advice and my fertilization schedule, you’ll bounce back quickly by late February.

GardenLine with Randy Lemmon

GardenLine with Randy Lemmon

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