Why is green growth showing up so fast after seeding?
Grass seeds typically take weeks to sprout, meaning sudden green growth appearing within days is usually pre-existing grass or fast-germinating weed seeds stimulated by watering rather than the new seed. This makes it difficult to tell if a lawn renovation is actually succeeding or if weeds are just taking over the bare spots.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- 2 of the 9 people here also raised “Why is my overseeding failing to grow?”
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.
- 1Checking seed bag ingredients for fast-germinating grass blends like ryegrassDid this help you?
- 2Assuming the new growth is pre-existing grass sprouting from underneathDid this help you?
- 3Mowing the grassDid this help you?
- 4Confirming what kind of seed was put down with the service providerDid this help you?
- 5Waiting longer for slower-germinating seeds like Kentucky bluegrass to poke throughDid this help you?
- 6using selective herbicides like Weed B GonDid this help you?
- 7comparing plant pictures to online forum postsDid this help you?
- 8Spraying selective herbicide once the lawn is establishedDid this help you?
- 9Waiting to see how the grass maturesDid this help you?
- 10Trying to guess the plant type based on appearanceDid this help you?
- 11Checking seed or straw compositionDid this help you?
- 12Treating the lawn with diseaseX or brand fungicide from Home DepotDid this help you?
- 13Asking for visual identification help on lawn care forumsDid 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 are these really tall sprouts. Reseeded with Blue Resilience Zone 5b two weeks ago.. Thick stem.”source ↗
“Did I disturb some dormant weed seeds? Maybe these have always been here I just haven’t notices.”source ↗
“I just seeded with Blue Resilience and have the same”source ↗
“I swear this isn’t Bermuda- although it acts like Bermuda. It springs up over night. I’m just confused on what it is exactly. It’s like a fake Bermuda.”source ↗
“These brown spots appeared suddenly after rain.”source ↗
“Im in central texas. Lawn is st augustine. These brown spots appeared suddenly after rain. I havent spread anything except fire ant killer in several years. Any ideas?”source ↗
“I put down super turf II from United seed about 10 days ago and I’m getting this two leaf grass everywhere that I didn’t have before. Does anyone know what this stuff is?”source ↗
“Aerated, seeded my yard and have been watering frequently but only seeing this come up and not much new grass. Been two weeks.”source ↗
“Trying to identify this, it grows so unbelievably fast it’s wild.”source ↗
“At first I thought it was just crabgrass until I saw a post earlier today with Johnson grass, so now I’m not too sure.”source ↗
“i get the same a few towns south of you in Columbia - crabgrass 😭”source ↗
“Is this a grassy weed? Or is it just light green from overwatering / need more fertilizer ?”source ↗
“So I did a whole front lawn renovation this past weekend on Saturday. Sunday we got hit with a lot of rain which made me paranoid thinking most of my seeds washed away since my front lawn is sloped. Today is Wednesday and saw some green which really shocked me.”source ↗
“Can this be KBG germinating after just a few days? I thought KBG take atleast 2-4 weeks to see results.”source ↗
Where this came up
People with this problem also raised
- 4How to get rid of moss without hurting new grass seed
- 11Are yellow patches in newly installed sod dead or a fungus?
- 5Why is my grass getting bright lime green patches?
- 48How do I figure out what kind of grass I have?
- 7Why are there strange symmetrical patterns and holes in my lawn?
- 25Is my dead lawn patch caused by grubs or fungus?