Today: Jul 23 , 2019

Should Vinegar Be Your Go-To Weed Killer?

Review of Vinegar as a Weed Killer

Watters Weekly Garden Classes

July 9 - Safe Pets in the Garden, Pet Heat Stroke and Garden First Aid Dr. O'Sullivan, veterinarian, Pets can get in trouble and get into things they shouldn't, summer heat stroke while hiking, eat unsafe plants on the trail and more. Dr. O'Sullivan covers Holistic Frist Aid and Outdoor safety with our pets. A local veterinarian with impressive Purdue credentials, but also specializing Chinese medicine for pets, even acupuncture. This is a dog, cat and bird friendly class, so come early and bring your pets to the nursery. Author of "Take Two Bones & Call Me in the Morning".

July 16 – Perennials with Impressive Blooms. Increased rain in July make the ideal month to plant perennials in the gardens. Students learn how to design seasonally for a continual four season bloom in the garden. Notable mentions will be the local native bloomers.

July 23 – Herb Garden Designs from Beginner to Pro – Summer is the ideal time to add herbs to the garden. More that just culinary, herbs are a staple plant for the mountain landscape. Learn which herbs are best in the kitchen, reseed by themselves, javelin proof, evergreen and more. You will be an herbal pro after this class. Free to gardeners of all ages.

July 30 – Easy Grow Roses – There are so many more choices than your grandmother knew. Learn the difference between hybrid tea, floribunda, shrub, carpet and so much more. Placement is critical for an easy to care for rose. Students learn the best varieties, care and placement for non-stop blooms. Free to local gardeners that want more fragrance & color in the yard.


Aug 6 – Secret Gardens with Hedges & Privacy Screens. Not all plants are created equal when it comes to intimacy in the garden. This class shows off the best plants, fastest growing, height, thickness, spacing and the local technique that gets them to fill in FAST! You can block unsightly neighbors and enhance your view, or pesky traffic and cut noise and light pollution. Experts will be on hand to help individuals with unique situations.

Aug 13 – Ground Covers and Vines to use in place of lawns without the mowing and care of grass. Soften that rock look with these easy to grow alternatives to a grass lawn, but take the summer heat all that rock throws off. These fast growing plants stay low & tight with less care needed than a lawn mower dreamed of. Learn which evergreen shrubs, herbs and vines soften all that rock, hold the soil from eroding, cool in summer while looking good all year long. A few plants go a long way when students know plants to use locally.

Aug 20 – Juicier Fruits, Grapes & Berries. Central Yavapai county is famous for our wine grapes but you can grow so much more. We will have experts on hand that can share the best producing raspberries, a blackberry bush that produces HUGE berries, more table grapes, gooseberries, currents, elderberries and more. Join in the garden harvest to big, juicy fruiting plants.

Aug 27 – Drip Irrigation Design and Installation (Free) It's time to turn that irrigation back on. Learn the benefits of drip irrigation, the best emitters and parts, how to set a system up or add to it. With the right system you can save water and have healthier plants at the same time. We will also go over how to properly set up and run an irrigation clock.

Vinegar experiments have been conducted in the Lain gardens with interesting results. Vinegar and herbicides made with acetic acid show promise as broad spectrum herbicides. 

Effectiveness seems to depend on the type of weed, its maturity, and the concentration of acetic acid in the vinegar. Household vinegar is a 5% acetic acid solution. Stronger concentrations of 15%, 20%, even 30% acetic acid are also available, but as they are highly caustic, be careful handling these stronger concentrates.All concentrations of acetic acid, including household vinegar, seem to cause weed foliage to brown some within 24 hours.

Young, tender weeds like crab grass are highly susceptible to treatment with household vinegar. However, the roots are often not killed and the weeds reappear within a few weeks. Repeated applications are more effective, and stronger concentrations of acetic acid work even faster with a better, longer, knock down.

Vinegar works really well on weeds between the cracks in sidewalks. I suspect that the heat from the pavement helps the process. I’ve had less luck with vinegar on perennial weeds and those that grow in shady areas; they turned black, but rallied and grew back. These tougher areas needed a couple of repeat applications at 3 day intervals to eventually die back. Sadly, they reemerged again in a month or so.

You can find stronger concentrations of vinegar sold for canning purposes. These work faster and longer than household vinegar, but are caustic and should be handled with extreme caution. Keep it off your skin and away from your eyes!

 All vinegars contain acetic acid, but not all acetic acid is vinegar. Acetic acid is created by fermenting alcohol. Household vinegar has a 5% solution of acetic acid made from the fermentation of plant products like grapes and apples. Stronger concentrations of acetic acid and even synthetically created acetic acid are available. 

If the acetic acid in a product is created by the distillation or freeze evaporation of plant sources, like household vinegar or the stronger concentrations sold for home canning, it is considered organic. Acetic acid made by synthetic processes is not.

 Being an acid, vinegar can lower a soil's pH a bit. However, acetic acid breaks down quickly in water, so any residue is gone after the first irrigation cycle or rain.

To use acetic acid as an herbicide: 1. Spray directly on the foliage and try for saturation without much run-off.2. Don’t apply before watering or if rain is expected, as water breaks down acetic acid.3. Avoid spraying on windy days to prevent this killer from drifting onto plants you don’t want to damage or kill.

I had much more success with BurnOut by Bonide, which showed better results and was much safer than the super strong vinegars.This product mixes a stronger solution of citric acid with clove oil. The dual combination allows the stronger acid to penetrate deeply into the leaf and stick to local weeds better than straight household vinegar did.BurnOut is difficult to find locally, but is available in three different sizes at Watters Garden Center.  

My personal goal is to keep my vegetable and herb gardens organic for my family's health, for our pets, for the birds, but finding an effective organic product that really works has been difficult.  BurnOut is approved for organic gardening, and safe for use around people and pets. It killed all types of actively growing weeds and grasses while proving remarkably rainproof once it was dry. BurnOut worked really well around borders, driveways, sidewalks, even around the base of mature trees, around buildings, fence lines, barns and pastures, in the greenhouses, and other areas where it was applied.

After experimenting with so many different types of vinegars I unflinchingly recommend the switch from vinegar to BurnOut for our Watters customers.

Plant of the Week is the Purple Magic Crape Myrtle.  You'll be wowed by the amount and intensity of purple blossoms that shadow this impressive bush.Leaves emerge as bold red foliage in spring, turning to a bright green just as the purple flowers erupt in summer. It blooms twice: first in summer, then again in autumn, and at $39 it's easy to add more than one to any garden or landscape. 


FREE Gardening Class on July 16 is about Perennial Summer Flowers. These impressive bloomers come back year after year. Increased rain in July makes this the ideal month to plant perennials. Students will learn how to design for a continual four-season bloom in a garden or landscape. Emphasis will be given to local native bloomers. 

Until next week, I'll be helping gardeners kill weeds here at Watters Garden Center.  

*Disclaimer - Vinegar is not labeled for use as a herbicide, so I'm really not able to recommend its use. But experiments as a gardeners is recommended.I can recommend the us of Burnout by Bonide corporation because of its label and Arizona registration. Household vinegar works well on young weeds. Repeated applications seems to improve effectiveness.Don't bother trying to kill older weeds, thistle and perennial weeds with vinegarThey simply grow back to quickly.Switch to stronger caustic solutions or Bonides fast acting 'BurnOut' for a better weed killing experience that still keeps the garden organic. 

Ken Lain, the Mountain Gardener

Ken Lain is attracted to sunshine, beauty, happiness, success and health through gardening, and wishes to point the way to others. Throughout the week Ken can be found at Watters Garden Center located at 1815 W. Iron Springs Rd, Prescott, or contacted through his web site at