I am sure multiple products (any sort of herbicide) in a large enough quantity/concentration will do the job. Basically you poisoned the soil.
I would be worried in using the amount or concentration needed to do this would affect ground water and runoff contamination.
Plus you don’t want anything growing there, but what about 5, 10, 15 years from now when you no longer own or use the property? The next owner/user may want to plant something there. And if they do get something to grow, like a vegetable garden, and eat it they could ingest chemicals beyond what is healthy and have no idea they are.
If you can handle treating it every couple of years, kerosene is pretty good for this. Our marching band used it to stripe yard-lines on the practice field back in the day.
No idea who decided this or why, and I make no environmental warranties. I just know the kerosene straight-up killed the turf and it took at least 2 years to grow back.
That’s a category 1 danger material, and highly toxic to some presumably non-intended organisms.
If using: READ THE LABEL. The entire label. Follow instructions. Use only according to the label: protective gear as described, proper dilution for the specific use, anything about location/time of day/etc, keeping animals including other humans out, preventing re-entry for the specified period, anything and everything else on the label.
I presumed that post #1 was asking whether any such thing is available that’s practical and sensible to use. If they just want to know how to destroy the place and don’t care about any consequences whatsoever, that’s a different issue.
I do use the appropriate PPE. The listed hazards are eye damage/irritation (I wear a face shield) and toxicity to aquatic life (I am in the desert, the nearest body of water is two miles away). It dries very quickly and is listed as safe once dried.
I’ve tried vinegar, salt, Round Up and a propane torch on my 14x40’ gravel parking area. All with mixed results. All methods required repeat applications in the same year.
RM43 lasts all year.
I bought it at Tractor Supply and had to sign for it. TS staff recommended it and said that our local farms use it all the time.
I mix it 7 parts water to 1 part RM43.
I follow the safety directions (gloves, eye protection, P95). I never use it on a windy day and I drew a skull and crossbones figure on my garden sprayer and mixing jugs.
I don’t like to use chemicals on our little piece of the planet. Aside from the parking pad, everything else is chem-free. I don’t even use weed and feed. I’ve been working on getting the yard transitioned to Dutch White Clover, but it’s been a slow process. $30 for 5 lbs of seed.
OP only stated that they wanted a weed killer strong enough to prevent growth forever. They did use the example (or metaphor) of salting the earth, which in every historical and literary sense has referred to total destruction of agricultural or horticultural capacity.
Clearly you prefer that they do this in an environmentally responsible manner, but until the OP has clarified their position in that regard, it’s not accurate to pretend that this is a condition they care about, nor a condition that should constrain the discussion.
We could just ask the OP: do you care about downstream effects at all? Do barriers like concrete or gravel satisfy your condition, or do you specifically want a chemical that leaves a bare patch of barren dirt forever?
It doesn’t necessarily need to “strong” enough. I was thinking there may be weed killer pellets that you sprinkle on the ground that would release painful weed-death over the course of years. That would meet the criterium of nothing growing again (or at least for years).
Barriers are a possibility except weed cloth, or whatever it’s called, is a no go as it just holds the weeds more firmly to the ground and doesn’t work. I have had some success will laying down plastic bur for one path specifically it just won’t work. And of course the question with using plastic is what happens to the rain and water? My patio extension needs the water to drain away from the fences and be absorbed by the ground. I am eventually going to run paths and patios with rocks or pavers and putting this hypothetical weed-killer underneath to help prevent existing weeds that I haven’t caught from growing through the cracks/rocks. That’s why the spot weedkillers like RoundUp wouldn’t work for this particular prophylactic plan. And naturally I don’t want to destroy the water table or have it leach and kill everything else.
We’re supposed to recommend things while deliberately leaving people ignorant of known hazards to themselves and others?
News to me.
Anyway, the OP has clarified their position, and no they don’t want to ruin the water supply or kill unintended organisms.
What you’re looking for is a broad-spectrum pre-emergent herbicide.
I doubt anything currently legal for use is going to last forever, though; or even multiple years. There are various designs of crack weeders (hand tools) on the market; if you don’t want to do that chore, or hire it done, I’d again recommend some form of solid pavement. Even that won’t last forever without cracking, but if properly done should last quite a while, and I believe you can get various colors. It seems that you’re talking about a fairly small area with soil around it (presumably with something growing in it) that can absorb the runoff; in which case again if properly designed it shouldn’t cause problems.
Ortho used to make something called TRIOX, but I haven’t seen it in decades. I think it turned out to be too toxic. It’s use was to poison the soil, and its effect lasted for years after an application.
Ortho still makes Triox, but it’s not advertised as “forever” (at least not its current formulation,) but just “up to one year.” In fact, looking at the label it seems to be pretty much the same ingredients and strength as the RMA3 mentioned above.