I'd like to hear your thoughts, experiences or recommendations about using 20% vinegar to kill the top growth of annual weeds at this time of year. I want to delay flowering and seed production to allow me time to put down mulch that will smother them and prevent further germination. I really dropped the ball last year in a very large hillside area where I was starting to get on top of the annual weeds and, as a result, they have spread their seeds everywhere. With such relatively warm temperatures so far this winter, the weeds are growing like crazy!
Interesting question, Margot. I did a quick search and saw this https://www.thespruce.com/best-weed-killers-4173508 where there is mention of a commercially available 20% vinegar solution. You'll see in the comments on the product that they didn't like the fact the weeds had to be pulled. The product mentioned does not appear to be available with the usual suspects in Canada. These are their recommendations for homemade weed killers. Good luck in your quest!
Thanks for your comments, Pieter. There are vinegar products for sale online in up to 75% concentrations but it sounds like 20% is strong enough to kill the top growth of weeds - in the right conditions. So that's the problem for me because the weeds are already past the 2- or 4-leaf stage and the weather is too wet and cold to expect good results. It is also quite expensive for the amount I would need. This article does a good job outlining the advantages and disadvantages of using vinegar. https://extension.umd.edu/resource/vinegar-alternative-glyphosate/ I have tried all the suggestions listed in 'homemade weed killers' except for rubbing alcohol which I'll experiment with when the weather warms up. (I almost burned down the house using a propane torch.)
Margot, years ago I worked in a camera store that had it's own B&W photolab attached where they used acetic acid for a stop bath to stop development before going into the fixation bath. So, I thought I'd check and see the ins and outs of its use for your intended purpose and came across this. One of the things they show under uses and benefits is the following: Gardening: In concentrations of 10 to 20 percent, acetic acid can be used as a weed killer on gardens and lawns. When used as an herbicide, the acetic acid can kill weeds that have emerged from the soil, but does not affect the roots of the weed, so they can regrow. Sounds to this my not necessarily be your answer... Addendum: Just followed the link you gave and I see it states the same con....guess there's no easy answers other than apply and repeat and repeat..
@Margot, I used to volunteer at a conservation area and of course couldn't use chemical products to control weeds in paths etc (for obvious reasons) so we used a 3 part vinegar solution and it worked very well. The recipe is: 1 cup salt, 1 tbsp dish soap (it was recommended to us to use Dawn brand but I can't recall why) and 1 gallon white vinegar. I think the 20% strength would be ideal. The idea is that the salt and vinegar break down the cell structure of the weed and the soap is a surfactant that allows the mixture to penetrate the weed. At the very least, it will delay the weed going to seed and continuing the cycle. Those weeds that are already growing in late winter/early spring always seem to go to seed long before we venture out into the garden after the cold rains gradually decline. Good luck. In the link it describes the success of vinegar even on Canada Thistle. spray-weeds-with-vinegar
Yes, that is exactly what I'm aiming to do - to buy time. Thank you for your advice. Snap Weed (Cardamine hirsuta) is the worst, blooming and seeding seed so quickly in late winter. I'm reluctant to use salt in areas where I'd eventually like to plant because it is said to move very slowly through the soil but I think I'm going to spring for a litre of 20% vinegar. I'll report back on my success (or lack of).
Hello Margot - if you want to try - you mention “online” I’ve seen strong clear white cleaning vinegar at Home Hardware at the BC Coast it’s in their website - I can’t see the % in photo https://www.homehardware.ca/en/25l-white-vinegar-all-purpose-double-strength-cleaner/p/4581225
Thanks, Georgia - I've seen that too but, like you, couldn't see the percentage of acetic acid. 'Double strength' could be only 14%; hard to tell. It sounds like 20% is about right. I was all set to order 20% vinegar from Amazon but then discovered that a local cleaning supply company sells 25% vinegar. The price is reasonable so I'll give it a shot. If it doesn't work to kill the top growth of weeds, at least I'll be able to clean with it. :-( I tried boiling water a few days ago but it's very labour intensive and not very effective. I wish there were a kind of wand that would produce hot steam instead of a flame like propane weed killers. Knowing me though, I'd probably burn my toes.
Here mostly 30% vinegar and 5% one are available. I always buy 30% and make a 5% solution by myself. Using vinegar as a herbicide would still be pretty costly and would probably cause acidification of soil (our pH is ~ 5.5...5.8, no need to make it lower).
The soil is a community; applications of noxious materials like strong acids and salt are detrimental to the inhabitants and systems of this community. If an area of small ephemeral herbaceous plants cannot by leveled by a string trimmer then throwing a comparatively inexpensive material like a bulk load of hog fuel onto them will definitely ruin their day. And cover their seed bed, improve general soil conditions by mulching the involved space.
I guess I could smother the weeds with something like hog fuel and then remove it to work on manageable sections at a time. That just might work! My goal is to buy time so the weeds won't go to seed before I can pull them. It will be an ongoing challenge because the neighbour's place you can see in the photos is full of the same weeds. Here are a couple of photos showing about a quarter of the space I want to tame. Thanks to everyone who made suggestions.
The hog fuel would be left to function as a mulch. That prevented additional mass germination and the need for weeding the whole area going forward - clearing the mulch away after a time and resuming weeding would defeat the entire purpose of the exercise.
You can't really tell from the pictures that that large slope is terraced with natural outcroppings and scree - basically a huge rock garden. There is virtually no soil except for few pockets. My vision is to plant BC native plants including groundcovers in amongst the rocks so I want to feature them, not cover them up.
@Margot I may have missed this earlier in conversation … have you identified the « weeds » names of species ?
Collections of various tiny to small plants positioned among rocks so as to produce an alpine effect tend to require many hours of grooming on a recurring basis.
Exactly! To my shame, I was on top of the weed situation until last year when, I have to admit, I became so upset with the challenges of drought, rabbits and deer that I simply ignored my garden for the summer. Now it will literally be an uphill battle to whip it into shape again. I have always enjoyed weeding and am prepared to spend however many hours necessary but I would like to somehow kill the snap weeds (Cardamine hirsuta) in particular before they start going to seed in late winter.
Oh yes - THAT weed the first I ever saw it was in plant nursery stores 25? Year ago what a beast - tho earnest and sturdy! i am obsessed and pull them out when I am at the nursery having a browse Maybe this is your tea meditation weeding time every fine day - they are easy to pull that’s for sure I don’t know why we think this « weed » is a curse —- however it irks me like lint on clothing :)
Shot weed likes fine-textured, highly organic germination surfaces such as exposed (no covering like pebbles or chips) potting soils in planted containers, fine grade bark or the impractical purchased compost mulch products that are too popular. In these prevalent situations numbers of the plant come up readily.
Snap weed (shot weed and other unflattering common names) will settle for ANYTHING! I have found plants barely 1/2-inch tall with fully formed seed pods. I hate it and admire it at the same time.
