The Green Horse section provides practical information on managing environmentally sustainable horse properties, readers stories and tips, as well as advice and articles from equestrian experts in their fields.
Vol 36 No 5
In this issue of The Green Horse you will find the following articles:
A safe place in an emergency
by Jackie Rive, Brookby Herbs
Keeping Cool in the Summer Heat
Weed Watch- Sycamore Leaf Poisoning - often fatal in horses
by Nicola Field
Grass For Horses - part 3
by Mariette van den Burg
Water Quality on the Horse Property by Liz Beavis
Great Recycling Tips
Using Vinegar to Fight Weeds
by Wendy Elks
by Andrea Carmody
USING VINEGAR TO FIGHT WEEDS
by Wendy Elks
Many horse owners are familiar with apple cider vinegar, a popular product for both people and equines for the health-giving benefits its proponents say it can provide. Though many of these claims remain unproven, vinegars have been used for centuries for their antibacterial, antimicrobial and antiviral properties, and are currently enjoying a resurgence in popularity as a non-chemical alternative in many applications around the home, and in the stable.
Distilled from fermented grapes, apples or grains, apart from culinary or herbal supplement usage, vinegars are used in industry and as a non-chemical cleaner and mild herbicide. It is effective for these purposes due to the acetic acid produced naturally through the fermentation process and the oxidisation of organic carbohydrates. Commercial vinegars are typically labelled at 5% acidity – acetic acid being the naturally occurring active ingredient.
While chemical herbicides are the most effective for killing weeds, since they are systemic - going to the root of the problem and killing the plant from the inside out - for those seeking non-chemical treatments vinegar is a cheap and natural alternative. Costly apple cider vinegar is best reserved for dietary use, but white vinegar is very cheap and just as effective.
When sprayed on weeds (or any plant) the acetic acid in vinegar quickly burns the leaves, either killing or harming the plant by starving it of moisture, oxygen and nutrients. Sprayed as a weed killer, particularly in hot sun, it works very quickly. A conventional sprayer can be used, which should be rinsed out afterwards to avoid corrosion of parts. A smaller hand-worked spay bottle has a finer mist than the backpack type – which would also be quite costly to fill with straight vinegar, as it is most effective used undiluted.
Robust or well-established weeds will need repeat applications, but it is worth trying vinegar on smooth broadleaf weeds and invasive plants like oxalis, on paths, driveways, around yards and in areas where horses may ingest weeds treated with chemical herbicides. Vinegar won’t move through the plant to kill the root, as systemic herbicides do; it simply draws all moisture out of the leaf. Depending on the variety of weed and how mature it is, the root may die. Young weeds might not have sufficient reserves to put out new growth, and older weeds and new growth will be weaker, so may die with repeat application of vinegar.
Plants with a waxy coating or a hairy surface may not absorb the vinegar so well, making it less effective. Vinegar applied to the soil as a full strength drench could kill the root directly, but this is not recommended as roots from other plants could also be affected.
There are recipes around for stronger natural herbicides based on vinegar with added salt and detergent to make them more effective, but these will also have more negative effects on the soil.
Vinegar is non-selective so it should not be sprayed indiscriminately. All acids are highly corrosive. It’s powerful stuff, so although it is a natural product, it can still do harm to the environment if used without care. Vinegar will also lower the pH of soil, making it more acidic. The effects of vinegar on soil microorganisms are unclear, but eliminating them by overdosing with any product will reduce soil fertility.
On any organic property weeds form part of plant diversity and play a part in signalling soil condition. But for places where weeds are unsightly, such as gravel areas around stables and yards, vinegar can help eliminate pesky weeds without overloading soil with synthetic chemical toxins.