Lawn Watering Scheduler

Find out how much water your lawn needs and how to deliver it: inches per week, days per week, and how many minutes to run each zone (with cycle-and-soak so it soaks in instead of running off).

About this tool: how long should you water a lawn?

The Rest of the Lawn

Lawn Feeding Calculator

How much nitrogen your grass wants over a year, split into feedings that land in the 0.5 to 1.0 lb window, in pounds of the bag you actually own.

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Seeding & Overseeding Calculator

Pounds of seed for a new lawn or an overseed, the window to sow it in, and how to water it through the first month.

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Lime Calculator

Whether the lawn needs lime at all, and how many bags of which kind if it does, worked out without a soil test.

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About this tool: how long should you water a lawn?

The target is inches, not minutes

Two sprinklers running the same half hour deliver very different amounts. Cool-season lawns want 1 to 1.5 inches a week in a northern summer, rain included. The same grass further south loses more to heat and wants up to about 2 inches, which is why this tool asks for your zone. Warm-season grasses want 20 to 40% less than a cool-season lawn in the same place, buffalograss least of all.

Find out what yours put down

Set straight-sided tins around the zone, run it 15 minutes, average the depths, multiply by 4 for inches per hour. Output ranges from 0.25 to over 1.5 in/hr, so a copied schedule is often four times wrong.

Deep and infrequent

Two or three soakings a week, not a little daily. Aim to wet the top 6 to 8 inches: a screwdriver should push in that far an hour after watering.

Water early

4am to 9am. Evening watering leaves blades wet overnight, which invites fungal disease.

Dormancy is a legitimate choice

Brown is survival, not death. Half an inch every two or three weeks keeps the crowns alive. What kills a dormant lawn is being repeatedly half-watered awake.