Managing lawn irrigation efficiently is commonly overlooked. In winter, days are shorter and cooler, making lawns grow slowly or not at all. January is a good time to tune up the sprinkler system and prepare your lawn for the dry months ahead. Drought tolerance can be developed so your lawn can withstand more stress and still look good. This lawn will have a deep and extensive root system that will go longer between watering. Here are some tips to help you cut overwatering with the bonus of drought conditioning your lawn to make every drop count:
How long to water?
As the seasons change, keep in mind that only the frequency of watering changes; the amount of water stays the same. Adjust run time for each zone to put on ¾ inch of water. To determine sprinkler run times:
• Use empty tuna or pet food cans (6 to 10) scattered in watering zone 1 to figure out how many minutes it takes to apply ¾ inch of water for that zone.
• Take average of all the cans. If any cans are empty or near empty there is a water distribution problem that needs to be addressed; this will cause dry areas.
• Set irrigation controller for that many minutes for that zone. Controllers have an instruction label attached or one can be downloaded from the manufacturer.
• Repeat this calibration test for each watering zone, as they all differ in how long it takes to apply the recommended ¾ inch of water during each irrigation.
Gradually, over up to six weeks or longer, grass and landscape roots will spread deeper and establish in the 8- to 10-inch-deep moist, sandy soil. Age of a lawn has little to do with rooting depth except when the grass is first planted. Fill soil containing more clay type material may need less than ¾ inch; coarse, sandy coastal soils may need more. In time, your lawn will establish a more uniform appearance with less thatch and a deeper root system. For details, see Using the Irrigation Controller for a Better Lawn on Less Water at edis.ifas.ufl.edu/document_ep235.
When to water
Restrictions allow you to water weekly, but your lawn doesn't necessarily need water that often. Less frequent, but thorough, irrigations will help establish a healthier lawn with a deeper, more viable root system. Water the lawn on the next allowed day if you see:
• spots in the lawn that turn bluish-gray.
• footprints that remain in the grass long after being made.
• many leaf blades folded in half lengthwise.
Install a rain sensor switch
This simple but effective accessory will de-activate an automatic irrigation system after an adequate rain and prevent unnecessary irrigation. Rain sensors are available at irrigation and home improvement stores or can be installed by irrigation contractors.
• Overwatering encourages lawn diseases, weeds, excessive growth, runoff, ground water pollution.
• It wastes your money on high water bills and remedial lawn treatments.
• It also wastes a limited freshwater supply.