Should I kill crabgrass in late summer or wait for spring?
Killing a heavy crabgrass infestation in mid-September is rarely effective because the plants are already mature and will die off naturally with the first frost anyway. Waiting for the seasonal die-off and applying a pre-emergent herbicide in the spring prevents new seeds from germinating, which stops the endless cycle of trying to salvage a weed-choked lawn by hand.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 25.5× 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.
- 1scalping the lawn and seeding in the fall while planning to apply pre-emergent in the springDid this help you?
- 2Applying a healthy dose of weed controlDid this help you?
- 3Aerating, seeding, and fertilizingDid this help you?
- 4Mowing at a minimum height of 3 to 3.5 inchesDid this help you?
- 5Letting the crabgrass die off naturally during the frost and applying a pre-emergent herbicide in the springDid this help you?
- 6Manually pulling out the crabgrass during the growing processDid this help you?
- 7Using prodiamine or mesotrione pre-emergent productsDid this help you?
- 8having a vendor spread weed killer multiple timesDid this help you?
- 9laying partial sodDid this help you?
- 10Heavy dethatching, aeration, and overseedingDid this help you?
- 11Ripping up the worst areas to reseedDid this help you?
- 12Raking in fresh topsoil and a thin layer of peat mossDid this help you?
- 13Top dressing seeds with compostDid this help you?
- 14Mowing at a higher setting (55-60 mm) to protect young grass rootsDid this help you?
- 15Considering selective weed killers like Dicophar but waiting for the recommended 6-month establishment markDid this help you?
- 16Waiting until spring when the growing season is over to address the weedsDid this help you?
- 17Killing the entire lawn with chemicals and starting overDid this help you?
- 18Accepting it and turning the area into a putting greenDid this help you?
- 19Spraying Tenacity with a surfactant over multiple applicationsDid this help you?
- 20giving up and letting the clover thriveDid this help you?
- 21using an iron-based control spray as a defoliantDid this help you?
- 22spraying triclopyr along with a surfactantDid this help you?
- 23Remove by handDid this help you?
- 24Do nothing and let it die in the winter since it's an annualDid this help you?
- 25Spray Drive XLR8 after 4 mowsDid this help you?
- 26Apply more MesotrioneDid this help you?
- 27manually ripping out weeds to avoid spraying chemicalsDid this help you?
- 28using a scheduled weed and feed treatmentDid this help you?
- 29aerating and overseeding yourselfDid this help you?
- 30hiring professionals to completely rip up the yard and install sodDid this help you?
- 31doing nothing and just keeping the lawn mowedDid this help you?
- 32Living with the crabgrass in the fall, letting it die off naturally, and applying a pre-emergent weed killer in the spring before it germinates.Did this help you?
- 33Overseeding bare spots with fescue right before the first freeze to help choke out weeds by spring.Did this help you?
- 34pulling the crabgrass by handDid this help you?
- 35Pulling up the clover manually using a narrow tool like a screwdriver to get the root, ideally when the soil is wet.Did this help you?
- 36using bioadvanced 24hr killer to kill them nowDid this help you?
- 37using grubx as a preventativeDid this help you?
- 38Applying fast-acting curative treatments like 24-hour grub killersDid this help you?
- 39Treating neighbor's property to prevent migrationDid this help you?
- 40Manually digging out and removing grubsDid this help you?
- 41Using nematodes or biological controlsDid this help you?
- 42Killing the crabgrass with Quinway once the lawn was mature enough, then reseeding and spreading compost.Did this help you?
- 43killing the crabgrass with QuinwayDid this help you?
- 44reseeding and spreading compostDid this help you?
- 45applying starter fertilizerDid this help you?
- 46Treating the soil with chemical grub killers like BioAdvanced 24hour Grub KillerDid this help you?
- 47Applying Milky SporeDid this help you?
- 48Manual removal and disposalDid this help you?
- 49Overseeding and raking seed into the canopy in the fallDid this help you?
- 50Applying pre-emergent in the spring (mid to late April, or split applications)Did this help you?
- 51Keeping the lawn mowed short to minimize seed droppingDid this help you?
- 52Manually pulling the crabgrassDid this help you?
- 53Digging it out and seedingDid this help you?
- 54Digging it out and laying sodDid this help you?
- 55Pulling the weeds manually in mats or clumps before they seedDid this help you?
- 56Overseeding thin areas of the lawn to help grass compete with weedsDid this help you?
- 57Applying grub killerDid this help you?
- 58Using Grubkiller Plus for immediate controlDid this help you?
- 59Applying Imidacloprid as a systemic for longer-term controlDid this help you?
- 60Using beneficial nematodesDid this help you?
- 61Applying Triazicide (which was ineffective against grubs)Did this help you?
- 62Switching to Bayer 24 hour grub killerDid this help you?
- 63Watering the lawn continuouslyDid this help you?
- 64Considering hiring a sod guy to resod or reseed the lawnDid this help you?
- 65spraying the unwanted grass to kill itDid this help you?
- 66keeping it if you don't mind the appearanceDid this help you?
- 67pulling it all upDid this help you?
- 68verticuttingDid this help you?
- 69weed killing the patchesDid 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.
“Until the crabgrass attack in full force. Being a novice I let it go to long before I took care or it.”source ↗
“I've been using GrubEx for several years, but the last few have delt with grub damage in late summer early fall.”source ↗
“I have stayed away from curative treatments because I didn't want to harm other insects in my yard like bees, worms, etc.”source ↗
“I dug up at least two dozen of these damn things from a flower bed. Are these lawn grubs and do I need to worry about them eating my lawn?”source ↗
“Entire yard looks great after a month of over seeding but this clover patch is getting bigger. When and how would you deal with it”source ↗
“I live in Northern NJ, and slowly this summer my lawn in this one location has been turned dryer, and more silty then solid dirt.”source ↗
“I have found some sort of larvae that is in the dirt about an inch down or less. It almost seems that every square inch of this patch has one or two in the ground.”source ↗
“What kind of pesticides or treatment can be done to this area to try to fix it? Do you think I will have time before winter to have it get fixed?”source ↗
“Realized after mowing in late August that we had so many problem areas - looked like dying poa and just matted thatch buildup.”source ↗
“I can’t believe how many times I detatched a section of the yard (pictured below), but everytime I felt like we were exposing enough soil…it just looked the same the next day!”source ↗
“This started in July of this year. 1st pic was full of green grass right before a cut. Next week was the second Pic, light brown patches.”source ↗
“When my lawnguy was digging the holes he pulled out grubs and said I need to keep applying the insecticide.”source ↗
“After confirming it was grubs, I found out triazicide does not kill grubs so I bought the 24hr grub killer.”source ↗
“I have actually put a lot of it into my lawn and it looks nice and green but the wider blades look much different compared to other lawns around me.”source ↗
“Did a full lawn renovation the last couple weeks and have crab grass popping up with my new seed.”source ↗
“Grass was seeded 12 days ago and is coming in nicely but so are certain patches of crabgrass.”source ↗
“Every year I deal with some grub damage. I put grub control down, but it doesn’t seem to help.”source ↗
“Located in NJ. like title says, lawn is at least half crab grass. Being mid Sept, does it make sense to kill the crab grass or do I just wait for it to die and add pre emergent in the spring?”source ↗
“I am really struggling to try to make the lawn look nice. Picture is of the front yard and how full it is of weeds, crabgrass, and other stuff.”source ↗
“Still doesn’t look bad but I have peppered crab grass throughout now. I did not put pre-emergent down in the spring.”source ↗
“Should I just scalp, Dethatch, bag, and overseed. Then in the growing process just be adamant on pulling out the crabgrass? Or should I just wait till spring and apply pre-emergent like I should have.”source ↗
“It has been overrun with every kind of weed there is.”source ↗
“In just 6 months I'd say a relatively healthy yard with maybe 10% weed coverage has become more like 85% weed coverage.”source ↗
“Need advice on our lawn and bent grass "infestation."”source ↗
“Is there any other way around this extreme measure?”source ↗
“I’m fighting this battle right now.”source ↗
“Looking to control clover. It’s gotten a pretty big foot-hold in my back lawn this year.”source ↗
“I got so much clover this year I just gave up and let it thrive.”source ↗
“Yea this year it exploded and I’ve heard this from other ppl as well.”source ↗
“The issue is that it isn’t so much “in” my lawn as it is *replacing* it lol. Large areas are getting blanketed out.”source ↗
“What should I put down on my lawn in the fall if my crabgrass is out of control I’m in the Midwest Kansas City area”source ↗
“So, how would I go about eliminating the crab grass and restoring grass around the stones?”source ↗
“I was having this same issue along my fence.”source ↗
“little bastards will wreck your roots before you even notice the brown patches. skunks and raccoons will tear up your yard digging for them too which adds a whole other headache”source ↗
“I’ve already noticed parts of my lawn browning… I thought it was the summer heat. Guess I was wrong.”source ↗
“My yard was like yours. Crab grass city but salvageable with the already established grass under it.”source ↗
“How should I address this section of what looks like Bermuda that is slowly expanding into my fescue lawn. Dig it out and seed? Dig it out and lay sod? Some other solution?”source ↗
“Hmm, I cooked myself then, been overseeing it for a while and didn’t realize this is what it looks like lol I’ll have to look into options, is the only way to get rid of it to spray it?”source ↗
“Really frustrating because I restated the whole lawn this year and it looked amazing for a while. Now it’s full of annual meadow grass again.”source ↗
“Please help! Irish lawn, about 2 months old. I put out seed and fertiliser, and strangely on the bits where I put out fertiliser I now have a crazy amount of docks, with some thistles for good measure.”source ↗
“I have no idea what to do, because I don't want to harm the grass that I've gained, yet I'm afraid that the docks will completely take over and basically destroy all my hard work.”source ↗
“I am a new home owner and was handed a really weedy front yard. I would like to improve the yard and am seeing conflicting information on the best steps.”source ↗
“I am clueless, no idea what kind of grass I have (if any) and am unsure of what kind of herbicide to use to start the renovation.”source ↗
“I had similar issues when we bought 4+ years ago.”source ↗
“Learn from my 3 year nightmare 😂”source ↗
“This has recently taken over the back area of my lawn. It grows daisy like flowers and is easily pulled in a clump. It has spread pretty quickly while I was away for work for a month. It’s also very damp underneath and helped mushrooms grow. It’s mostly in one area but I have it spread throughout the yard in varying sizes. Any help identifying and treatment would be appreciated!”source ↗
“Until the crabgrass attack in full force. Being a novice I let it go to long before I took care or it.”source ↗