Our lawn is in appalling need of a weed-killing, and I found a half-bottle of some “kills everything but bermuda and bent grass” stuff—Weed-Be-Gone, I want to say? However, I think the bottle is about ten years old. Would it still be okay to use?
It won’t hurt anything to try it but the active chemicals have probably broken down and become inert by now and you’ll be spraying worthless chemicals on the lawn. I’d just pick up a new bottle at the local nursery or hardware store given the relatively low cost of herbicides.
I read this as, “Does killer weed go bad?”
But you might want to call your local Dept. of Health or Waste Management or Environmental Protection and ask the best way to safely dispose of old chemicals.
What are the active ingredients? Should be clearly listed on the bottle…
And not all herbicides are cheap, especially if you buy them in concetrates.
DMA salt of 2,4-D (2,4-Dichlorophenoxyacetic acid) seems to be the main one. I can’t make out the rest.
2,4-D is a very common broad-leaf herbicide. Some forms have an indefinite shelf life–pick a weed and give it a shot.
Ortho Weed-B-Gon isn’t one of your more pricey herbicides. I had assumed that it’s not a trigger spray but rather a concentrate for a hose-end sprayer. Seems a waste of time to spend an hour spraying the lawn with impotent chemicals instead of shelling out $15 for a new bottle.
If it is a trigger spray, go find a weed and try it. Weed-B-Gon isn’t fast acting though so it’ll take a while to see results even if it is still working.
Well, all I really care about is whether the chemicals fermented, and will cause my lawn to rot. 
If they don’t work, there’s hardly any wasted effort other than spraying for a few minutes.
So, thank you for the advice, reassurance, etc. I’ll give it a try later.
Is there any lawn left to save? If so then use a “Weed and Feed” type of lawn application. It will kill broad leaf plants and fertilize the bent grasses.
This thread reminds me of that Far Side cartoon.
I keep seeing the weed killer bottle holding the other gardening implements at gunpoint: “When Weed Killer Goes Bad.”