Can I plant grass seed in 90 degree weather?
High heat prevents cool-season grasses like turf-type tall fescue from germinating properly and stresses young seedlings. Tossing seed down now without waiting for temperatures to drop below 85 or 90 degrees usually results in wasted seed and dead grass, which is why many landscapers choose to postpone seeding until late September.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 27.5× more often in r/lawncare than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Waiting until temperatures stay below 85 or 90 degrees before seedingDid this help you?
- 2Watering frequently throughout the day (four times a day for five minutes)Did this help you?
- 3Switching from impact sprinklers to rotary sprinklersDid this help you?
- 4Increasing frequency of daily watering cyclesDid this help you?
- 5Replacing coco coir with traditional soil or peatDid this help you?
- 6Watering twice a day instead of three times due to time constraintsDid this help you?
- 7Rescheduling the seeding dateDid this help you?
- 8Shallowing watering them about 5 times a dayDid this help you?
- 9Laying down some Peat moss before germinationDid this help you?
- 10Laying down some more seed next weekDid this help you?
- 11running irrigation up to 5 times a dayDid this help you?
- 12covering the area with strawDid this help you?
- 13watering every 1 to 2 hours for short intervalsDid this help you?
- 14using a slit seeder for bare areas to help shield from the heatDid this help you?
- 15Watering frequently (multiple times a day) to help seeds survive high temperaturesDid this help you?
- 16Proceeding with seeding immediately despite the heat and adjusting soil amendments laterDid this help you?
- 17Delaying seeding until temperatures break or seeding later in the seasonDid this help you?
- 18Using weekly morning wateringDid this help you?
- 19Applying organic fertilizers and aerationDid this help you?
- 20Adding gypsumDid this help you?
- 21Applying disease control productsDid this help you?
- 22Mowing at a higher setting with sharpened bladesDid this help you?
- 23Using grub killerDid this help you?
- 24Keeping it watered and hoping for cooler weatherDid this help you?
- 25Watering at night using an in-ground sprinkler system to offset temperature issues and frost risks.Did this help you?
- 26holding off on planting until temperatures finally dropDid this help you?
- 27putting less effort into the seeding process in case it failsDid this help you?
- 28praying for snow or planning to switch to a xeriscapeDid this help you?
- 29Watering twice a day for around 10 to 20 minutes depending on the zone, soil, and shade, adjusted over the first few weeks.Did this help you?
- 30Hiring local gardenersDid this help you?
- 31Raking the soil after algae appearsDid this help you?
- 32Adjusting sprinkler durations and timingDid this help you?
- 33Installing artificial grass patches over problem areasDid this help you?
- 34Watering manually using hosesDid this help you?
- 35Installing an above-ground sprinkler setup connected to a timerDid this help you?
- 36Checking soil moisture depth with a screwdriverDid this help you?
- 37Accepting a dormant brown yard during the summer monthsDid this help you?
- 38Maintaining two separate sections of lawn for different seasonsDid this help you?
- 39Waiting for cooler temperatures in late October to avoid excessive watering.Did this help you?
- 40Watering much more frequently to keep the seeds constantly moist in high temperatures.Did this help you?
- 41Proceeding to seed immediately and watering heavilyDid this help you?
- 42Setting up sprinkler zones on an automated timer like Rachio with multiple short watering intervalsDid this help you?
- 43Waiting until temperatures cool down before addressing thin areas or overseedingDid this help you?
- 44waiting until later in the year or around Thanksgiving for re-seeding windowsDid this help you?
- 45cutting grass higherDid this help you?
- 46blasting water to keep seeds from drying out and dyingDid this help you?
- 47relying on irrigation systemsDid this help you?
- 48performing mechanical weed removalDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“What’s done is done but just looking for some reassurance that I haven’t made a mistake.”source ↗
“Did I make a mistake by seeding this weekend or did I make the right decision?”source ↗
“Does this mean I just have to be fine with my yard being brown during the summer?”source ↗
“First time growing a lawn from bare soil, and I could use some guidance.”source ↗
“In a few patches, it looks like tiny seedlings emerged and then died. Meanwhile, just a couple of feet away, the surface stays wet and has a green film that looks like algae or moss.”source ↗
“During this heat, should I change the sprinkler schedule or hand-water only the drying patches? How should watering transition over the following weeks with different-sized seedlings and sun/shade zones?”source ↗
“How can I distinguish seedlings dying from drying out versus staying too wet/damping-off?”source ↗
“Planning on reseeding and getting it going again I have TTTF but we're still getting 90-92 degree days can I just toss it down and water or do I need to wait till end of september when temps stay below 85.”source ↗
“I’ve been wanting to re do my backyard, I bought lots is top soil and grass seed BUT this is the weather for the next few weeks 🫠”source ↗
“Do I wait to over seed and top-dress until the weekend because of the spike in temp?”source ↗
“I recently moved into a new place and they put down sod for us but now it’s dying?”source ↗
“I haven’t cut it because that seemed to make it worse??”source ↗
“I wanted to overseed at the beginning of September, but it has been far too hot for it. We were getting days in the mid 90s, so I decided to hold off.”source ↗
“Still getting days in the upper 80s/low 90s. Weather typical for August and July, not September, and too hot to plant grass seed”source ↗
“This is really late for me. Probably too late, depending on if October decides to really cool down.”source ↗
“Same general location also using TTTF. Original plan was to dethatch, aerate, top dress, and seed the 17th but Im considering postponing the seeding until the heat is consistently below 90 degrees.”source ↗
“Coco coir on top of new seed, appears to be drying SO fast!”source ↗
“By the time I the 4th one finishes, the soil is already dry on the first area at least on the outer edges.”source ↗
“I can’t imagine going 4 hours between waterings as my soil dries out in less than an hour?!”source ↗
“Lawn Company I use for seeding and aeration insisted it was totally fine and probably better to go ahead with seeding on Monday 14th. This seems to hot no? We are also on a water restriction in Charlotte. It’s a bluegrass fescue seed”source ↗
“Then the forecast changed to 95ish all this week.”source ↗
“will they be able to survive the next 4-5 days of intense heat?”source ↗
“I’m in the same boat as you.”source ↗
“my direct sunlight areas are barely patchy and I’m not happy with the germination so far”source ↗
“Definitely jumped the gun on seeding this year”source ↗
“we have irrigation but I hear even with that it might be too hard to keep seeds moist”source ↗
“as you can see, it’s still hot as blazes here in Volunteer country!”source ↗
“I am watering my back yard every 2 hours for 3 minutes and the front every hour for 5. I am praying the front germinates. It is showing signs in some areas, but I fear I will have to reseed in two weeks.”source ↗
“Given this god awful heat dome, what is your sequence and timing starting to look like?”source ↗
“I think I'm running out of time to wait for a meaningful break in temperatures, then try to soil test, spray, aerate, seed, and fertilize before the bottom drops out.”source ↗
“I'm in a similar boat, just gonna go for it and water like crazy.”source ↗
“I am struggling to fix the lawn for past 3 seasons.”source ↗
“pretty much no grass grows ( except for short time in fall and spring) mostly white dead grass that just peels off and weeds take over whole summer.”source ↗
“after every mow there are brown patches underneath .”source ↗
“Very frustrated and need your help.”source ↗
“This year, average ground temperatures are still running in the 80's and air temperature has been mid-low 90's.”source ↗
“Based on all my research, I'm at the last recommended window to drop seed. Cool season grass (tall fescue). How long can I realistically wait?”source ↗
“my soil temp is still 87 degrees”source ↗
“How frequently did you water an for how many minutes each time”source ↗
“I usually watered twice a day. I was battling the heat, so I was doing little under 20min the first week.”source ↗
“Mixing them will look patchy as hell come summer. The warm season stuff will green up while your fescue and kbg start to struggle with the heat, so you end up with weird brown and green blotches everywhere”source ↗
“if you want green in summer too you'd basically have to maintain two separate sections of lawn which is a huge pain”source ↗
“Hasn't rained here in North GA in like 2 months. Keeps going north or south of us. I hate watering my lawn, but I think I'm there.”source ↗
“We went from 'trying desperately to keep the grass alive' to 'flash flood' to 'perma-drizzling but still sauna' this week. I want to get off the ride.”source ↗
“SoLawnwise just aerated and over seeded my lawn in late September while it was still 96°. I've been watering twice a day and haven't seen a single seed sprout. Do I ask them to do it again?”source ↗
“I need help with my lawn and so far every gardner ive hired lacks basic grass knowlege.”source ↗
“I am unable to get hang of this and want rich perfect grass on which we can sit on and enjoy in winters.”source ↗
“Last week a layer of algea spread on top of soil. I was running sprinklers 5 min morning and 3 min evening.”source ↗
Where this came up
People with this problem also raised
- 179Why is my overseeding failing to grow?
- 3Should I use a fungicide on brown grass during high humidity?
- 22How to keep a lawn green during a drought with water restrictions
- 4How to fix a scorched lawn without renting heavy equipment
- 38Can you plant grass seed late in the season after missing the window?
- 20How to water new grass seed with a full-time job