Ag 101 Week 18

Not Your Grandma's Vinegar

This time of year, I get questions ranging from how to keep things alive to how to kill them. One thing I’ve talked a lot about recently is what can farmers and gardeners use for weed control that is relatively inexpensive yet effective.

My first response always includes the obvious cultural practices including, but not limited to-

Maintaining clean fence rows and perimeters

Mow/graze in a timely manner

Cultivate on a regular schedule

Use aggressive cover crops or inter-seeding – by aggressive I mean one that grows fast

When that isn’t enough, and you need to use another alternative my first suggestion is 20% or 200grain vinegar. Just as the title said, this not your grandma’s 5-10% vinegar she uses for pickling or cleaning, but the gnarly eat through your pants kind.

For home and backyard growers

The homemade concoctions you read about, in my experience, are not sufficient even for the home/backyard grower. In my opinion, you need to ditch the dawn/salt/vinegar mix and use the more effective strength vinegar I’m going to talk about. It will save you time and effort, ultimately saving you money as well. Remember size vs. scale? If not refer back to Week 4

So, what kind of vinegar am I talking about – 20% or 200grain vinegar, commonly referred to as Ag or Food Grade. It can be purchased online or at some farm and garden type retailers.

Some points to think about when using 20% vinegar

1.     It is not a systemic herbicide, meaning it will not enter into the plant's metabolism and kill it that way. It is a burn down that may have to be applied more than once. Target younger weeds at the appropriate stage of growth for maximum efficacy.

2.     It is non-selective, it burns whatever it comes in contact with even the person applying it. Be careful and strategic when using it and don’t do it on a windy day.

3.     Make sure you cover as much surface area of the plant as possible, contact is critical.

4.     Growers I work with have found the following rates to be effective

                 For tank mixing 8-10 gallons/acre with as little water as possible

                 For backpack and hand sprayers 50/50 vinegar & water

5.     The general rule of thumb

If spraying to kill spray during the hottest part of the day when the sun is the most intense.

There are several other products on the market for the chemical free, natural, or certified organic grower. They are usually oiled based and have been found useful as well. One of the most common that I have worked with is Nature’s Avenger. For several years I recommended that you dilute it with vinegar. After talking with a field rep from Nature’s Avenger, they have found there is no increased efficacy of either the vinegar or their product using it that way.

My suggestion to a grower is to start with a single chemistry first while maintaining good cultural practices. If weed pressure escalates and cannot be efficiently controlled with one chemistry instead of mixing products, alternate spraying with a different one.

Have questions – don’t hesitate to ask