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Glyphosate/Re-seeding question

Posted: August 8th, 2020, 9:17 am
by falcon
I have some spots on my lawn that need to be killed off for various reasons. There was a handicap ramp from the prior owner that left a dead spot that filled in with crabgrass this year. I have another bare spot with various weeds that was beat up from tractor work. And finally, I have some large patches of clover that I hit with Triclopyr 10 days ago. Normally I would hit them again this weekend, but it turns out there wasn't much turf in those patches, so they will need to be re-seeded. I don't think I should bother hitting it with Triclopyr again - I'll just hit it with Gyphosate.

My plan was to hit everything with Glyphosate today and re-seed in 10-14 days. I bought a blend of 35% TTFF, 35% FF, 20% KBG, 10% PR. I currently have a Northern Mix. I understand that this might not look fantastic, but the folks at Valley Green recommended the blend because the front lawn has a very sunny half that blends into a pretty shady half under some spruces. The front is irrigated. Another area I am re-seeding is very sunny and non-irrigated, and was told the cultivars in the blend have good drought tolerance as well.

Right now, I am just trying to learn as much as possible in preparation for a potential full renovation in the years to come. I'm trying to get it looking above average, but not perfect...there is no way that is happening without a full reno.

Anyone see any issues so far?

The second question...yes, I've read the Compare and Save 41% Glyphosate label already, and I still need some clarification. The label contradicts what my memory says is common advice given here...maybe I am wrong.

The issues:

1. The label says not to mow the lawn for 7 days before or after application. Is that correct? I don't think I've seen people say the same here.
2. The label says not to re-seed lawn grasses for 7 days after application. I would have sworn I've seen people here say it can be done the next day.

Thanks for the help!

Re: Glyphosate/Re-seeding question

Posted: August 8th, 2020, 10:07 am
by andy10917
It can be done the same day - many of us have done it without incident.

Glyphosate works on green-tissue, and they're trying to maximize the green tissue with the mowing. Just up the amount of Glyphosate some and you'll be fine. Extra surfactant also helps.

The rest seems OK.

Re: Glyphosate/Re-seeding question

Posted: August 8th, 2020, 10:48 am
by MorpheusPA
Totally agreed. Not only the same day, but as soon as you're sure it's completely dried (in full, bright, warm sun and a slight breeze, as little as an hour).
I do wait to be sure it's completely dry to make certain there won't be any impact on the seed as I'm not certain it would have any (probably not, but over-caution is always good).
I also used it the same day as seed-down over a few dozen square feet without any consequence at all.

Re: Glyphosate/Re-seeding question

Posted: August 8th, 2020, 12:42 pm
by falcon
Thanks, guys. The lawn already looked so much better this year with the the help of everyone, particularly Andy, who did my soil interpretation. I’m looking forward to seeing another improvement next year.

Re: Glyphosate/Re-seeding question

Posted: August 11th, 2020, 6:53 am
by falcon
One follow-up. I had to spray near some new Hydrangeas. I protected them from drift by holding a large piece of cardboard up while I sprayed. Because the Hydrangeas are new and their flowers are huge, they want to flop right onto the ground in the area I sprayed with Glyphosate. It's now been two days since I sprayed...are these Hydrangeas going to die if they touch the grass/weeds that are covered in Glyphosate? I used a non-ionic surfactant as well, if that matters. I'm concerned the morning dew will re-wet the glyphosate and be dangerous to the flowers. Right now I have cardboard propped up protecting everything...very strange looks from passersby.

Re: Glyphosate/Re-seeding question

Posted: August 11th, 2020, 7:41 am
by andy10917
You can remove the cardboard. Any incidental contact with the RU on the grass/dew will not harm the Hydrangeas at this point. RU was originally developed to be a plant growth regulator. At very, very low application rates, it can actually increase plant growth, At the "normal" application rate, it kills plants. Somewhere in between those two rates, it can slow growth. At the levels you would find at this point, it will cause no problems with a plant the size of a Hydrangea, through incidental contact. I apply it near my Hosta sometimes, and don't use cardboard or anything, and the small amount of drift that occurs causes no ill effects on a healthy, larger plant. That's not advice to be wanton and sloppy, but tiny amounts do not kill or harm larger plants.

Re: Glyphosate/Re-seeding question

Posted: August 11th, 2020, 8:18 am
by falcon
Andy, you are an amazing resource. Thank you.

Re: Glyphosate/Re-seeding question

Posted: August 11th, 2020, 11:23 am
by MorpheusPA
+1. I don't even bother with the cardboard when spraying and spray right in the (flower) gardens. Incidental spray has no visible impact, as a general rule.

Re: Glyphosate/Re-seeding question

Posted: August 11th, 2020, 6:40 pm
by mobiledynamics
Interrrresting read, as I thought windrift RU on any shrub, flower or anything in the -garden beds- was no bueno. Never have masked it off, but have done a pre and post leaf spray as -mitigation- for the just in case