We grow food in our back yard garden. Part of the reason for this is to limit our exposure to pesticides and chemical fertilizers used to grow commercial produce. Ellen and I use organic gardening principles and are always looking for new options. Last week we learned about using white vinegar to control weeds instead of RoundUp.
Standard white vinegar is a 5% acid solution. When you spray it directly on grasses and weeds, the acid burns them and kills them. Or, so the story goes. I decided to try this for myself and see what happens.
The Weed Killing Test
I filled up my pump sprayer with 2 gallons of white vinegar purchased from my local Piggly Wiggly grocery store. This is the standard 5% acid white vinegar you find in any grocery store. You can also purchase horticultural vinegar that has significantly higher acid concentrations (it is NOT for human consumption!) Horticultural vinegar is also significantly more expensive, so I wanted to start with the cheap stuff. Plus, what I read said that it should be potent enough for my needs.
Next, I sprayed the paths between my raised beds in the garden, the side parking area in the front of the house, and a patch of heavy grass where I am planning a swing-set play area for the girls. The unwanted plants were a mix of weeds and grasses along with some other fast spreading ground cover plants.
The white vinegar burns whatever plants it touches. So, I avoided any areas where it might get onto plants I want. I waited for a time with low winds and kept the spray wand low to the ground to minimize any over spray.
It is important to get a good coating of white vinegar on the plants, but you don’t need to saturate everything.
Within a few hours I could clearly see that the areas I sprayed were yellowing and dead/dying. A few very hearty grasses had a little green on them the next day and I gave them a second dose of vinegar.
Since vinegar only kills the exposed growth, weeds that can re-grow from roots (or those that haven’t emerged from the ground yet) will come back. But repeated applications should eventually starve the root and kill those as well.
Tips for Best Results
White vinegar works best when applied on a hot dry day. The heat and lack of moisture will amplify the stress on the plant and kill it before it has a chance to recover from the acid in the vinegar. I think many of the people reporting poor results where applying the vinegar in cool or moist conditions where the plants could survive the shock of the acid.
Be prepared to spray again. Unlike a chemical herbicide, white vinegar will need more time to kill off unwanted weeds and grasses. Tougher plants might require horticultural vinegar for effective treatment. And, for poison ivy, I still use RoundUp. Sometimes it is the only effective option.
White vinegar is a very useful organic tool for killing unwanted weeds and grasses. But, it does have limitations.
Don’t expect to save time or money by using white vinegar. Vinegar costs a bit less than $3/gallon around here and you will need repeated applications to control deep rooted weeds and grasses. Chemical herbicides will end up costing less when the job is done. The main reason to go this route is to avoid the use of persistent chemical herbicides around your home and garden.
Another option for rapid weed control is a weed torch/burner. These also burn the top growth of the plant, but do it with a propane flame instead of an acid solution. For cooler climates and more moist conditions, the torch works well. I haven’t gotten one yet, but it is on my gadget list!