Congrats on your newly seeded lawn! We are excited for you to enjoy a space to do life and enjoy the outdoors.
This guide explains how to care for your newly seeded or overseeded lawn.
Overview: Lawn Care growing Seed
The grasses we plant in the PNW are “cool season grasses,” meaning that they usually remain green Fall-Spring and go dormant in the summer. We often attempt to keep them green all year long by watering them consistently in the hotter months of late spring and summer.
In order to keep your grass looking green all year round, you have to water consistently in the warm season. You cannot forget for a few days, as it is nearly impossible to get grass green again in the summer once it goes dormant and brown.
We recommend that you install an irrigation system, but if that is not in the budget at the moment then at minimum put a sprinkler on a timer on your hose bib. That investment is small, but will return dividends in mental sanity and maintaining your investment in reseeding your lawn.
Have a large lawn that can’t be covered by one sprinkler? Run multiple zones with a sprinkler attached to each. See options below for multiple zones.
Recommended Hose Bib Timers
Rachio Smart Hose Timer
Linked here. Our favorite hands down for ease of use and sustainable watering practices. These smart timers pack an upfront investment at nearly $150 for two zones or $100 for one, but allow for the greatest flexibility. The smart app will pause watering if there is rain in the forecast, allowing you to save water. The app allows you to run “cycle and soak” so that the total watering time will be done in smaller increments to allow the water to soak in rather than run off. You can also run it all remotely from your phone app.
We recommend putting a simple y-splitter on your hose bib so you can have the Rachio valve running to your sprinkler, and still have a normal hose attached as well for hand watering needs.
These timers work in sync through WIFI and the app, so you can add as many as you want to hose bibs all around your property. We personally have 4 total Rachio valves to water our grass and garden beds.
Rainbird Single Zone Timer
Linked here. This is a cheaper single-zone timer that allows you to water every 6 hours, so up to 4x per day. We like it for that flexibility at a cheaper price point than the Rachio. Note: it does not have smart watering features.
B-hyve Multi-zone Timer
Linked here. If you want a cheaper timer that also allows you to have multiple zones, this one works just fine. Nothing fancy, but we have used it with clients that need 2-4 zones on one hose bib. The nice thing about this is you can still use the y-splitter and put the timer on one side, and a hose on the other. Note: it does not have smart watering features.
You can learn more about irrigation on our Irrigation page.
Spring & Summer Lawn Care Watering
Overall: See how your grass reacts to the schedule you set, and water as much as it needs to stay green and grow how you’d like it to.
While the new seed is establishing (roughly the first six weeks) you need to water frequently to help the new seedlings root and establish. You essentially want it to always be moist and never dry out, but not to puddle as that will damage the seed.
Watering by Week
Weeks 1-2
Set your irrigation controller to water for a short period like 3-5 minutes every 8 hours. If it’s drying out too quickly then set it for every 4 hours. If this frequency is not possible with your irrigation controller then water twice a day at a time that works best for you.
If you are watering by hand, twice a day is ideal but if you can aim for at least once a day for the first two weeks that will work ok in periods of weather under 70 degrees.
Weeks 2-6
After two weeks, you can reduce the time of watering by 25% but you still do not want it to dry out completely.
Weeks 6+
Once established after 6 weeks: switch to longer waterings less frequently. How long depends on your sprinklers and output, you want it to be a deep watering that gets deep into the soil and encourages root growth. This is likely 10-20 minutes. You still need to water consistently during the warmer season to maintain a successful lawn, I’d recommend 3x a week unless it’s the deadheat of summer, then water every 1-2 days. If it is going to be 85+ for multiple days then water daily. The best time to water is in the early morning before sunrise in the 4-6am time period, this decreases evaporation but doesn’t leave water on the blades overnight to encourage pests or disease.
Early Spring & Fall Lawn Care Watering
If the lawn is receiving consistent rain, you do not need to worry about watering unless we have very dry spells for multiple weeks. In general, for Seattle, this rainy season begins in early October and lasts until May.
If you have a newly planted lawn in the Fall, follow similar directions to the Spring & Summer watering but you do not need to water as often if it is below 60 degrees.
Walking and Traffic
Do not walk on it until the seeds are established. After the first mow it’s ok to walk on it and have light traffic, but hold off on heavy traffic or play for the full 6 weeks if possible.
Mowing
For a newly seeded lawn, wait as long as you can. You should not need to mow it for 4-6 weeks unless it’s going absolutely crazy. This might sound overly simplified, but you’ll know when you need to mow.
If you are overseeding an existing lawn, then the existing grass will continue to grow while the overseeded areas get established and you don’t want those to grow too long. Waiting 2 weeks is ideal. Mow on your tallest mower setting above 3″ for the first 4-6 weeks and then decrease down to your desired height one setting at a time. You never want to remove more than 1/3 of the grass blade with anyone cutting.
Long-term, you’ll find that your lawn prefers to be mowed about once a week from late spring to late summer. In the early spring and fall, you will only need to mow every 2 weeks.
Fertilization
Don’t fertilize your lawn before the seeds are established. After that, you can do whatever you think is best.
We prefer natural fertilizers like topdressing with compost. If you used a lawn mix like 60/40, then that contained compost and you will not need to fertilize for several months.
If you would like an easier alternative that is better for the planet, we recommend the spray on pouches from Sunday. They use ingredients like seaweed and leave out harsh chemicals that are bad for kids, pets, and anything living in and around your yard.