New grass seed with weed killer?

Old 04-17-02, 05:59 PM
HandyRon's Avatar
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Cool New grass seed with weed killer?

I have applied the first round of scotts pre-emergent crab grass killer/fertilizer in March. I plan to apply the second round (includes broad leaf weed killer/fertilizer) in May. The lawn is very sparce in areas throughout the property. Could I plant new grass seed this spring, or have I ruined that chance by laying the weed killers. If so, could I plant grass this fall?
Old 04-18-02, 06:31 PM
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Hello Ron

Not sure what the active ingredient in Scott's CrabGrass Preventer is, but whatever it is will also stop 'regular' grass from germinating. I seem to remember that the old pre-emergent that was commonly found for crabgrass was Dacthal and it stayed effective for a few months. That would mean you should be okay seeding in the fall ( a lot of turfgrass varieties usually self-seed in August anyways).

To be absolutely sure, there may be a phone number or internet website on the packaging (if you still have it) that you could call to confirm the active ingredient and when it is alright to seed, or the nursery that you bought the product from should be able to tell you.

The broadleaf control shouldn't have any effect on seed sown after a few weeks.

Here's a link to Scott's (hope it is a North American link - didn't have a chance to explore it thoroughly...)

Good Luck

Old 04-27-02, 07:31 PM
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Weed killer and new grass seed

I just put down a weed and feed product. The label said wait one month before seeding. Well, in one month it will be too hot and dry to be thinking about grass seed here. So, I will wait until fall and concentrate on eradicating the broad leaf weeds until then. When temperatures get hot and the ground gets dry, grass becomes stressed. Chemical applications stress grass further. The weed and feed product I bought at the hardware did not have a name I recognized. They had no Scott's. So far, I can't see that it has done anything. Today I bought something to spray. The yard here has more weeds than grass.
Old 04-28-02, 05:07 PM
ct. arborist
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if i remember correctly i believe the acive ingredient in the scotts plus crabgrass control is pendimethalin,which will not allow new grass seed to germinate for aprox. 3 months,so i would wait until fall before doing any overseeding.
ron r.

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