Monday, May 23, 2011

Vinegar As Weed Killer

In our never-ending quest for a chemical-free garden, we've tried many things.  Almost anything we read in a book or online, we'll give it a try, if it makes some sort of horticultural sense.  You can read a lot of crazy things online......Anyway, we've tried vinegar before; vinegar as an herbicide is a very prevalent notion, as a matter of fact many of the organic herbicides sold in stores contain acetic acid, which is vinegar.  I had some leftover pickling vinegar, which at 7% acetic acid is a little stronger than regular table vinegar, which is 5% acetic acid.  I have read about a very strong horticultural vinegar, but it seems impossible to find.  I was happy to experiment with this pickling vinegar, because I'd rather buy fresh to start off the pickling season.  I chose a group of happy, flourishing dandelions on the driveway, out in full sun.  I applied the vinegar straight on one of our warmest, sunniest days last Wednesday.  We had two days of warm temperatures and full sun.  By Friday, the top growth was largely, but not completely, brown and crispy.  By Sunday, after a day of steady rain, the treated dandelions were flowering - yes, flowering!  Apparently, as an evolutionary protection, dandelions can complete their flowering even after being pulled or treated with vinegar!  The centre of the plants also looked like new leaves were coming!  So, not the kind of killing result one might get with, say, a glyphosate based product like Roundup.  As I understand it, the vinegar, combined with sun, dries out the leaf.  It is not absorbed by the plant and does not kill the roots.  However, defoliation is a severe set back for the plants, so I'm going to reapply - the less leaves the plants have the less they can perform photosynthesis and eventually I'll exhaust them!  I think that using vinegar as a weed-killer will work best on younger plants than I chose, and certainly, with persistence.  It's certainly less expensive than chemical herbicides and, for us, a much better choice than chemicals!  Keep in mind if you try this that vinegar will be what's called non-selective, meaning it will act on any plant it is applied to: if you try this in the lawn you will kill the grass that gets sprayed!  

1 comment:

  1. Interesting experiment. I've often heard of using vinegar to treat weeds but have never done it myself. Should I ever try, now I'll know what to expect.