Weeds - Roundup won't kill them

I always thought Roundup did a pretty good job of general weeds but the after spraying last week - the weeds are still growing happy and healthy. It did not rain for 2 days after I applied the Roundup. I soaked the weeds. What can I use that will knock them dead in a day or so? I have, in the past, used a consentrated product but I really want to kill these monsters that come up around my mulch, etc. It's just your basic weeds - no major problem.

Any suggestions?
Kathy

20% vinegar kills most things within 24 hours. It's not the household vinegar which is 5%. My neighbor gets it from an organic plant farm.

That sounds a lot cheaper than Roundup - and I just can't understand why it won't work. I'll look online and search out 20%. Thanks for the tip.

Roundup takes awhile to kill the plant. It inhibits it's ability to do something, but I can't remember what it is. I spray bindweed with roundup and it takes about a week for it to start looking like it's going to die, and then another week for it to dry up.

Unfortunately, the bindweed comes back, and looks like it's got the flu or hungover or something. If I can hit it again with roundup at that point, it usually won't come back again.

Vinegar kills on contact and is not absorbed into the roots. Great for annual weeds and not really all that effective on deep seated perennial weeds. At 20% it is NOT vinegar, it's acetic acid and will cause permenant eye damage (blindness). Please be careful.
Most likely you did not wait long enough for the Roundup to take effect. At least 7 days, sometimes more depending on temps, spray technique, etc.. It is absorbed into the roots so it will do a better job of eliminating the problem with less danger to the applicator.

I sprayed Roundup the 3rd week in May and still have those same, basic weeds. The top leaves are dead but that's it. I talked to a local Feed & Seed guy who said that Round up has only a very small percentage of the killing chemical - mixing a formula of concentrate will have 45 or more percent of that same concentrate. He sold both products and said if I didn't see a difference in a week he would refund my money. But he swears Roundup is a major rip off.

Thanks for the warning on the 20% vinegar, but where can I find it locally? What TYPE of store sells it? I have seen it online but the shipping for a gallon is more than the item.

Thanks guys.
k

What roundup product are you using?? Some contain more active ingrediant than others and I never used premixed stuff-that indeed will not do the job. I use Roundup concentrate and find it works quite well. at a 5% solution as the label specifies for tough weeds. Also conside your application and the weather along with the possible need to add a surfactant. You didn't cut before you sprayed, did you?? Wouldn't use 20% acetic acid on a bet...dangerous stuff!!

It's all about weeds.....lot's and lot's of weeds. I cannot seem to rid my lawn of these nasty little critters. The lawn is only a year old (new construction) and the soil leaves much to be desired. There are many bare spots on the lawn with tufts of grass growing here and there. It looks as if some very cheap top soil was used as well. I've started to add some new soil in some of the low spots. I've tried a few of the weed killers out there - round-up, ortho products, etc. Yes, they killed some of the weeds but also damaged the grass as well. Learn by experience I guess. I think the next time I'll try some napalm to get rid of 'em! LOL!!

Other than pulling up the weeds by hand has anyone else had much success with the variety of chemicals out there? If so, which brand/type do you use? It seems that a chemical treatment is only designed for the weeds that come through the sidewalks where there isn't much grass growing. It this true? As stated, I've already damaged some of the good grass with the overspray. Yikes!

Have you tried weedkillers that are specifically labeled for use in lawns? The lawn weedkillers have herbicides that kill broadleaf weeds but not grass. The standard broad spectrum weedkillers like Roundup kill everything so they will damage your lawn too.

Fortunately there was only minimal damage done..a spot here and there. Thankfully I didn't proceed any further. That's me though...just buying anything off the shelf that read "weed killer"...not thinking to look for the small print. I'll know better next time. Thanks for the advice. Can you recommend any specific name brand?

Sorry, I don't have a lawn so I've never bought them, I just know they exist! I imagine that Ortho and Scott's and some of the other bigger brands probably have them but since I've never used them I couldn't recommend one over another. Just look for the things that say lawn weedkiller on them and you should be OK.