How early can I spray roundup to nuke my lawn for a renovation in the spring?

[john5246]

Against the advice of people here I've decided to go ahead and do my lawn renovation this spring rather than fall. The mix will be Midnight/Bewitched at 50/50. Can I spray the glyphosate anytime or wait until I see some spring growth? I'm thinking of seeding sometime in May if weather permits.

What is the ideal overnight temps for best germination of KGB?

Also if the germination rate on the ticket indicates 85% do you factor that in to how much seed you put down. For example, if you are putting down 2lbs/1000 sq ft with a germination of 85% that means only 27.2 oz will germinate instead of the full 32oz of seed (2lbs). Anyone know how to calculate this since the additional seed you throw down will also have 15% not germinate?

[turf_toes]

You are overthinking everything.

You can apply roundup if the grass is green. If the temps are cold, it will take longer to kill the grass. But it will eventually work. I’ve applied in early March and seen it take five weeks to die. But it worked. The grass must be green.

The grass seed will germinate when it is ready. Why do you need to know an exact temperature? As you note, spring seeding isn’t a good practice. But it’s your call.

Apply seed at the suggested seeding rate 2-to-3 pounds per thousand feet.

Growing grass is simple. Don’t make an easy task hard.

[Green]

If you're going to Spring seed, why wait until May to kill, if it's green in April? That will just put you closer to Summer, making it harder.

85% germination is good, new seed. No need to compensate for anything. If it were 4 or 5-year-old seed, then you might have to use a little extra. You can test old seed yourself using moist paper towels in a bag.

[HoosierLawnGnome]

FWIW, if you have to seed in the spring, which I do this year, consider waiting until there is a lesser chance of frost.

[john5246]

If you're going to Spring seed, why wait until May to kill, if it's green in April? That will just put you closer to Summer, making it harder.

85% germination is good, new seed. No need to compensate for anything. If it were 4 or 5-year-old seed, then you might have to use a little extra. You can test old seed yourself using moist paper towels in a bag.

Well I need 1 week to let it die and then another 2-4 weeks to let weeds or anything I missed grow...then reapply. If it's green in mid april that would perfect I think. Mid may is the earliest I'm willing to risk throwing down seeds as we do have quite unpredictable weather here in the midwest.

[Green]

Yeah, that KBG germinates so slowly that it can be pretty cold sensitive. I don't think I personally would have the guts to do a KBG Spring Reno. TTTF, maybe, since it doesn't "pout" as long, so the cold probably won't zap it as badly. I'm sure you can make it work decently, though. Others have. I have no problems overseeding with KBG in the Spring, but I drop seed early, and accept whatever cold damage occurs.