The Q&A Archives: Crabgrass In New Lawn

Question: I planted a new lawn by seed, put in good soil, rototilled, used good quality seed, and covered with mulch. I noticed some crabgrass came up as I was beginning to plant and I pulled out all I could see, however more is coming up. I water 3 times a day, I dont let the mulch dry out. Question, the lawn is starting to show in a few places ( only been a week) how long after it is fully a lawn can I put on a crabgrass killer without hurting my new lawn or whould I just pull all by hand? Also am I watering too much, the temp here is around 70 degrees. As I said I am watering 3 times a day for 15 minutes each. As always thank you for your generous help. I know someone pays for this website, Is there somewhere I can join to help defray the costs? thanks... Dave Gale

Answer: Since your lawn is so new, I'd hesitate to use herbicides on it. Hand pulling the crabgrass is the best strategy for now. There is a corn-gluten based herbicide that acts as a pre-emergent against crabgrass and can safely be used in established turfgrass. I'd wait until next spring to apply it or any other crabgrass killer. As far as watering newly germinating seed, it's important to keep the seedbed moist until all the seeds have sprouted. Watering several times a day may be what is required so I don't think you're overwatering at this point. All of the seeds should germinate in 10-14 days; you can reduce watering when most of the seedlings are up and have grown 2-3" high. Once the blades give your yard a rich green cast you'll want to water less frequently but apply water deeply to encourage deep root growth. Depending upon weather, you'll probably water every other day or every two days. After you've hauled out the lawnmower and given your turfgrass its first haircut you'll want to put the lawn on a regular ration of one-inch of water per week, applied slowly so it percolates down and wets the entire root mass. The deeper the roots grow, the less reliant the grass will be on frequent applications of water. Again, depending upon weather, once or twice a week should be sufficient for your lawn.

We're glad you appreciate our advice! You are welcome to join National Gardening Association (the source of the answers to your questions) by logging onto the website ( and becoming a member. Details are on the website and include some "members only" benefits.

Best wishes with your new lawn!

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