Wherein Myrtle is Full of Pith (and Vinegar!)

Herbicides in our drinking water have caused Myrtle Maintenance Personnel no shortage of conniption fits; we either write about them or reference them seemingly incessantly.  “So, Mssr’s Smartypants, what is the alternative?”  Until very recently, the only documented alternative herbicide a dedicated organic gardener had to dreaded chemical herbicides was a garden hoe and a strong back.

We’re afraid you are still going to have to keep the hoe handy, as well as the strong back, but help is on the way.

The USDA has made note of a strong body of anecdotal evidence and has, within the past half-decade or so, begun some intensive studies of a potentially effective and surprisingly cheap organic alternative to commercial herbicides.  More than likely, you even have a diluted version of this wonder substance in your kitchen right now.  A 20% acetic acid concentration of plain ol’ vinegar has been proven in several clinical trials to be quite effective as a weed killer.

There are several caveats, of course.  For one thing, vinegar affects some weed species more adversely than others.  An application of between 80 and 160 gallons per acre proved to have 96% overall effectiveness in killing weeds, but the solution proved more effective against broadleaf weeds than against grasses.  For overall effectiveness including against grassy weeds, the concentration has to be high enough (in the 80 to 160 gallons per acre range) that broadcast applications during the growing season are contraindicated.

Lower concentrations, as little as 20 gallons per acre, would still be effective against broadleaf weeds, but not against grassy weeds.  In short, if you have crops in the ground, and you don’t want to use a nasty, disgusting, not-enough-reviled herbicide, your only alternative for removing weeds is still to get down on your hands and knees and yank the things out by the roots.

As you may recall, too, at Myrtle’s place we have all along been less concerned with weeds than have other gardeners.  We call weeds “hay” because they are as good as cash when it comes to the production of healthy chickens.  However, the fact remains that weeds in your fruit and vegetable garden reduce the yield of produce.  The chief advantage of vinegar is that it is a very targeted herbicide which can be applied with pinpoint accuracy and without damaging, or even altering, the pH or any other characteristic of the surrounding topsoil. 

By nature, if it runs off, it will be more dilute and therefore less impactful.  It is a natural substance which you can find (especially in our yard) wherever there are naturally occuring sources of decay.  Wild grapes, for example, are an excellent source of naturally occuring vinegar, and sure enough, if you look beneath a tree which hosts a mustang grape vine, you will find fewer weeds if you search through the purplish muck where the wild birds have feasted on fallen grapes.

A couple of other interesting notes from the studies (there have been several, and more are on the way):

• Adjuvants have been studied, and there are several which agricultural scientists thought were likely to be helpful, but the most promising additive is orange oil.
  
• No studies have yet been done with lower concentration vinegars such as one might find in your local grocery store; most are in the 5% acetic acid concentration range.  Simple math suggests that using four times as much vinegar at this lower concentration would be the equivalent of using 20% concentration vinegar; however, proceed at your own caution because they do studies for a reason.  Sometimes unpredictable things happen.
  
• Application to weeds on top of an active onion crop proved successful at weed control, but at higher concentrations of vinegar, crop damage and loss was significant.
  
• Crop yield studies are still underway; the most promising scenario so far seems to be the use of cover crops for winter weed management followed by vinegar application prior to spring planting with a “dead period” prior to seeding in order to allow the concentration to be naturally mitigated.

We at Myrtle’s will soon be undertaking our own trials, though we will be limited by several factors.  For starters our measurements will be undertaken with several limitations, not the least of which will be having to take the manufacturer’s word for it on acidity levels – we’ll report on usage with what’s on the bottle.  We could go out and buy some litmus paper, we suppose, but hey, we’re cheap.

We are going to start with an application to the weeds growing in our gravel driveway.   We will report on the approximate coverage of this space by weeds, give a rough breakdown of types, and an analysis of how thoroughly and how quickly they are reduced by the application of ordinary household vinegar.

Once we have dismantled the raised beds where this spring’s crops were planted, we will dig a wide-row/furrow system in our back yard, with a raised clay berm demarcating the border where our fence will eventually go.  This is the ever-exciting Phase I of a multi-phase project we will tell you more about as we get into it; the important thing to note here is that much of the space is currently covered by both grassy and broadleafed weeds, and this area will require a much more significant application of vinegar in order to kill off the existing foliage before fall planting, which starts in about three weeks.

Since this fall’s planting will be heavy on seeded rather than transplanted crops, the potency of the application will be a fascinating concern – are we dooming ourselves from the start this fall, or are we guaranteeing success?

Only time will tell.  Either way, we’re so excited we could pinch ourselves!

Happy farming!