A green lawn is nice, but too much water? That’s money down the drain and a recipe for moss, fungus, and weeds. Around here in Seattle, you don’t need to overdo it. Let me walk you through the right way to water your lawn without wasting time, water, or your weekends.
The Golden Rule: One Inch of Water Per Week
That’s it. Just one inch of water total each week—including rain. Most of the year, Seattle’s natural rainfall does the heavy lifting. But when we hit those dry summer weeks (usually July through early September), you’ll need to supplement.
Best Time to Water
Early morning between 5 a.m. and 9 a.m. is your sweet spot. Watering in the morning gives your lawn time to soak it up before the sun evaporates it or mold starts to form.
Avoid watering at night. Moisture sits on the grass overnight and can cause fungal issues, especially in shaded or poorly drained areas.
Avoid mid-day watering when the sun is strong. Water evaporates fast, and your lawn doesn’t get the full benefit.
How Long to Water: Do the Tuna Can Test
Here’s a simple trick I’ve used on hundreds of lawns:
- Place an empty tuna can or shallow container on your lawn.
- Run your sprinklers.
- Time how long it takes to fill the can to one inch.
That’s how long your system needs to run per week. Split that time between two or three watering sessions to avoid puddles or runoff.
Example:
If it takes 30 minutes to fill an inch, then do two sessions of 15 minutes each week.
Watering New Sod or Seeded Lawns
New lawn? That’s a different story.
New sod or seed needs more water early on to root in.
- Days 1–14: Water daily, maybe twice a day if it’s hot or windy.
- Days 15–28: Water every other day.
- After one month: Shift to the standard one-inch-per-week routine.
Don’t let new sod dry out—it’ll shrink and brown, and then you’re looking at a patch job.
Seattle-Specific Lawn Tips
- Don’t panic if your lawn browns out in late summer. That’s dormancy, not death. It’ll bounce back with fall rains.
- Overwatering causes moss and fungus. If you see mushrooms popping up, cut back.
- Shaded lawns need less water than full sun areas.
- Well-mulched beds help conserve water, too.
Need Help With Your Lawn?
At Lee’s General Landscaping, we tune up sprinkler systems, install smart irrigation timers, and provide watering plans for new sod installs and lawn restorations. If your grass isn’t looking quite right—or your water bill’s climbing—we can help.
Lee’s General Landscaping – Seattle, WA
Lawn care, irrigation, and practical yard solutions from your neighborhood pro.
Call or text Mr. Lee today to schedule a sprinkler check-up or sod watering plan.
