Are you searching for a “permanent” weed killer? A “natural” weed killer? An “organic” weed killer?
Don’t be fooled by marketing claims like:
“Kills weeds, not lawns”
“6 months of control with one application”
“New chemistry effective on over 200 weeds”
There is no silver bullet to make weeds magically disappear. Sure, chemicals work. They work really well on some weeds and less so on others. But their effect is not limited to the weed itself, regardless of marketing claims. An herbicide will make a broadleaf “weed” disappear from your lawn, but at the expense of the soil and biology beneath (and maybe your evergreen trees, as we saw with Imprelis).
And then there’s the organic weed killer solution of white vinegar and dish soap.
Spray it on an annual weed, and most will slowly die back, but it’s not effective on perennial weeds like thistle. It’s less harmful (arguably) than a registered herbicide, but also a poor long-term strategy. If you use too much, the soil becomes too acidic to grow anything for months.
I only recommend the white vinegar solution for use between pavers, cracks in cement, driveways, or stone paths where no plants at all – weeds or otherwise – are wanted. And don’t get me started on fabric weed barriers. They’re worse than useless and a great deal of trouble in the long term.
Should you use chemical weed killers in your vegetable garden or lawn?
Chemicals in a vegetable garden are a terrible idea unless you’re fond of ingesting them. This includes mulches with pre-emergent chemicals added (like Preen).
The best way to “kill” weeds in your flower or vegetable garden is to pull them by hand or use a tool like a CobraHead weeder, a weeding fork, stirrup hoe, Hori Hori knife, or your weapon of choice. Then mulch the beds 2″-3″ deep with organic material like wood chips.
In your lawn, you can control weeds by creating soil conditions in which grass will not only grow but thrive. More grass equals fewer weeds.
The only sure, lasting way to control weeds in your lawn is with simple, cultural solutions: corn gluten meal to suppress weeds in spring, aeration when necessary, a mulching blade for your mower, cutting the lawn at the proper height, proper seeding in fall, and organic amendments like compost.
The bottom line is, if you pull weeds as soon as you see them, they rarely get out of control.