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overseeding seed to kill weeds

Author: Matt Hagens

Table of Contents

If you do see any weeds pop up in the grass seed area, pull them right away! Don’t use a weed killer quite yet. Your new grass can’t handle an herbicide at this stage.

Step-by-step instructions for overseeding a weedy yard

Grass seed can be planted in a weedy lawn. However, if the weeds are very thick, you will get better results if you deal with the weeds first. If there are just a few weeds, pull the largest ones, then apply the grass seed.

Surprisingly, planting more grass is helpful to fend off the weeds! If those annoying weeds have less area to grow, they won’t spring up as fast. You asked, and I answered. Find out everything you need to know about weeds and grass seed!

Once your new grass is established and mowed two times, it is time for weed and feed! Follow the instructions on the package for the best results.

The weeds will win the battle for your yard in the summer. Use the time during the hot months to apply a weed killer or weed and feed. Get the weeds under control before it is time to plant seed in the fall.

You can spray it anytime you want leading up to seed day, and on seed day, but once your seeds germinate, you should NOT spray it again until the new gras has been mowed 2-4 times or 4 weeks whichever is longer.

Here is Table 1

Next, I found a product that is similar to Quincept in that it has the same active ingredients plus one. That is Q4 Plus . It has very similar concentrations of the active ingredients within the Quincept plus one more. That product says this:

ABOUT US

Can I Spray Weeds and Kill Crabgrass Now if I Plan to Seed In September/Fall Time?

It’s main purpose is to tell you that you should not use this product on Bahia, Colonial Bent, Centipede or St Aug, period. Doesn’t matter if you are seeding or not, you should NOT use this product on these grass types. It also warns you about using it in or around fine fescues – they must be part of a blend if you do.

So what this is telling us is that you can use Quinclorac 75DF on established grasses listed as “highly” or “moderately” tolerant. That is really all this chart is for. It has nothing to do with seeding, hence the word “established.” But you still have to look at this chart first to find out if you should even use this product in the first place.

Let’s stick with our example of Kentucky Bluegrass and you can see that it’s ok to apply quinclorac to the lawn to kill crabgrass 7 days before seeding or more. So right now, if you are let’s say 2 weeks away from seeding, you are welcome to spray away and kill that crabgrass dead. (note, this product turns crabgrass orange/red in about 6 days. But it takes much longer for the crabgrass to fully break down so likely some of it will still be there when you seed, just red and dead).