Most effective weed killer to buy in the US
August 3, 2018 3:02 PM   Subscribe

What is the most effective weed killer that they sell in the U.S.?
posted by Tziv to Home & Garden (17 answers total) 3 users marked this as a favorite
Can you define "effective"? There are weed killers that kill weeds but that are toxic to humans and the environment, like Round-up.
posted by jj's.mama at 3:05 PM on August 3, 2018

Roundup works pretty darned well.
posted by humboldt32 at 3:05 PM on August 3, 2018 [1 favorite]

Straight glycophosphate is the best combination of effectiveness, low toxicity and rapid breakdown. Its what most invasive spp programs use in upland areas. You do need to keep it away from water though and apply as advised.

Roundup makes a few different types of weedkiller only one of which is just glyco. The others will have additives or other herbicides that are longer lasting. Most are more persistent or more likely to pass through cell membranes due to surfactants etc. And the effects of the combinations are less well understood.

For selective herbicides, ie those that kill broad leafed plants but not grasses, look into the iron based ones. I've had very good luck with those and they are basically non toxic.
posted by fshgrl at 3:14 PM on August 3, 2018 [4 favorites]

I've always been satisfied with Roundup, but my neighbors swear by Bayer Weed Killer, saying weeds stay dead for up to six months.
posted by davcoo at 3:49 PM on August 3, 2018

My old man settled on a mixture of Roundup (glyphosate) and Crossbow (2,4-D) to apply to the relentless overgrowth in Oregon. I'm sure that you aren't supposed to do that, but he was an empiricist and not a rule follower.
posted by Glomar response at 4:19 PM on August 3, 2018 [1 favorite]

posted by clew at 4:42 PM on August 3, 2018 [13 favorites]

For spot application on walkways, driveway, patio, etc.:

Boiling water is 100% non toxic and effective. If you’re sure it’s near no desirable plants, you can pour on salt water or vinegar water, both kill most plants at high concentrations and have fairly low ability to impact areas beyond application.
posted by SaltySalticid at 4:50 PM on August 3, 2018 [6 favorites]

You don’t really tell us anything about at all your use case. Information usually helps solve problems.
But there simply isn’t any general answer. What is effective depends on what you are targeting and where you are.

In that light, I should also mention that mechanical removal is far more effective than just about any compound applied once or twice topically.

E.g. if I had to remove several woody saplings, I’d rip them out, because it would take dozens of applications of Roundup to kill them, and then I’d still have to remove the skeletons. But we have no idea what you are dealing with. Some clarification may help you get more useful replies.
posted by SaltySalticid at 4:54 PM on August 3, 2018 [3 favorites]

Weed Dragon propane torch.
posted by headnsouth at 6:55 PM on August 3, 2018 [4 favorites]

I agree that the question is quite broad. Pictures or description of specific weeds would help. A friend got rid of an invasive by cutting it and applying glyphosate(Roundup) to the cut stem. He wanted to keep his use of it as minimal as possible. It does appear to be longer-lasting and more toxic than advertised. Using the strongest herbicide is not the kindest approach to the environment.
posted by theora55 at 7:27 PM on August 3, 2018 [2 favorites]

You'll also have to define "weed killer." There are bare ground herbicides such as Frequency and Mojave that are extremely effective but must also be used very carefully as they will kill basically every plant in the area (including any runoff areas, which can be a serious problem). They're most commonly used for places like utility substations where preventing plant growth is important but human maintenance would be expensive.
posted by jedicus at 8:02 PM on August 3, 2018

Apart from broad-spectrum chems (kills most everything - which you normally don't want), all herbicides are plant specific (at plant family level), so what are your weeds? Narrow leaves or broadleaves, or a mix?

There are about 22 herbicide chemical groups so it is just a (not very simple) matter of matching problem to chemical.

Just, please, don't use anything with Picloram in it.
posted by unearthed at 10:54 PM on August 3, 2018

For the average person, there's pretty much two options:
Glyphosate (Roundup): this kills pretty much everything that's green; trees can resist it a bit, but anything that grows in a lawn, including grass, dies from it.
2,4D (in many things, including Weed and Feed): this is a broad-leaf specific poison, so it kills undesirables like dandelions, plantain, mustards, but also desirables like clover and decorative flowers. Although many promise it'll kill crabgrass, I haven't found it to do so. If it has defined 'leaves', it kills; if the leaves are long and thin like a grass, it is resistant.

Neither should be used around pets and should be washed off your skin ASAP, but as far as herbicides go they're quite safe. Now, there's industrial herbicides that get used on farms, which require training to use, which may be more effective for what you want to kill, but if you don't already know what they are, you should stay away from them.
posted by AzraelBrown at 4:09 AM on August 4, 2018 [1 favorite]

Pedantry note: glyphosate is not "glycophosphate". The glyco prefix would indicate that the molecule is based on a sugar, which glyphosate is not, and the phosphate suffix would indicate that the molecule contains a PO4 group, which glyphosate does not.
posted by flabdablet at 7:34 AM on August 4, 2018 [3 favorites]

Yeah it auto corrected it. I think it's spelt differently each time in my post.

Another note: Roundup sells more than one kind of herbicide. Read the label and don't salt the earth or break the law assuming all Round Up is the same.
posted by fshgrl at 10:49 AM on August 4, 2018 [2 favorites]

selective herbicides, ie those that kill broad leafed plants but not grasses

One of my pet peeves is the way herbicide manufacturers have managed to convince so many people that things other than grass, and clover in particular, don't belong in lawns for no better reason than the creation of demand for "selective" herbicides.

The only good reason to remove non-grass plants from your lawn is if they're spiky or otherwise unpleasant underfoot. A diverse range of species in a lawn makes for a healthy, resilient, low-maintenance lawn that looks after its own topsoil so you don't have to. Monocrop lawns are clear signs of derangement.
posted by flabdablet at 1:16 PM on August 4, 2018 [6 favorites]

Whatever you do, read the whole label carefully for the thing you want to apply before you buy it. You can Google the trade name + label. If you can go to a place with some expertise (local garden center > big box store) and ask for advice, that should help some. Or consider getting a reputable yard service to handle it so you don't have to deal with pesticide storage and disposal.

FWIW, Crossbow is not registered for residential use, only along fencelines. And be careful - a guy around here killed his neighbor's vineyard with drift from a crossbow application and a lawsuit is in the offing.
posted by momus_window at 2:11 PM on August 4, 2018 [1 favorite]

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