[CPA Nerd]

I have about a 300 square foot area of my lawn, and a handful of other much smaller areas, where there are grassy weeds that are not controlled by Ortho Weed B Gon. I don't know if it is quackgrass or nimblewill or something different, but it isn't working.

I am planning an overseeding in the fall anyway, so is my best bet to spray those areas with glyphosate now, let it all die, and simply reseed those areas in conjunction with my overseeding in the fall?

I am hestitant to try Tenacity because of the cost, repeat applications required, and the fact that I am planning an overseed and will be watering the yard in the fall anyway. Might as well kill everything in that area and start fresh.

Pros/cons????

 

[Suburban Jungle Life]

For low cost, I like the glyphosate option. I would prefer to know what I'm battling though so if it comes back after you have a nice lawn, you don't have to burn spots out. You can use a selective herbicide instead. Many here can help to identify the problem weeds. Take some pictures of the whole area and also some close ups. Take a super close up of 1 stem/blade you pull out of the lawn. The identifying characteristics are small so try to get it clear. Tenacity might not be the right one.

 

[Mykle_thelawnguy]

I hear you, I have poa annua(grassy weed) and I hear from popular guys on youtube that tenacity kills it but it's not on the label or on scouts step one for seeding which has it in it. The problem is you have to put preemergent down in mid-August and again a month later the same time you would be seeding. I'm on the fence too. Either go straight cowboy and seed in July, watering the crap out of the lawn and deal with those issues. So you can put pre-emergent down in Aug.

 

[Suburban Jungle Life]

Tenacity will suppress poa germination. You can use it at seeding time and depending on the timing, you can reapply it to give your new grass time to germinate and grow. Also, you can use ethofumesate to help control poa depending on timing and grass type. After a couple months, your new grass should have a few mows on it and then you can use pre-emergent for the rest of the year and next spring. Poa doesn't stand a chance using these options. It must be carefully timed though. I wouldn't try to seed in summer to avoid poa germination. Too hard to grow new grass in the summer.

 

[CPA Nerd]

For low cost, I like the glyphosate option. I would prefer to know what I'm battling though so if it comes back after you have a nice lawn, you don't have to burn spots out. You can use a selective herbicide instead. Many here can help to identify the problem weeds. Take some pictures of the whole area and also some close ups. Take a super close up of 1 stem/blade you pull out of the lawn. The identifying characteristics are small so try to get it clear. Tenacity might not be the right one.

Thank you. I am at work but had my wife take some pictures. I posted on the weed ID thread.

 

[g-man]

It looks like crabgrass. "Weed b gon + Crabgrass" or anything similar that has quinclorac in the active ingredients.