Dallas Morning News – December 31, 2020

Cool Season Weed Control (Update)

Since your Bermuda, zoysia or buffalo grasses are brown now, they are probably completely dormant and it’s time for one of the most effective weed control treatments of the year.

Spraying dormant turf with organic herbicides is easy and effective. With the summer grasses dormant, the winter “weeds” like rye, rescuegrass, dandelions, henbit and poa annua have germinated and are growing but still small. It’s now time to spray the entire lawn without damage to the summer grasses.

Cool season weeds like henbit can be sprayed and killed with organic herbicides while summer grasses are dormant

My vinegar homemade formula is full strength 8-10% pickling vinegar with 2 oz. orange oil and 1 teaspoon of liquid soap added per gallon of vinegar. No water. This simple formula works well any time during the winter when the summer grasses are dormant. It’s also effective on summer weeds but desirable green plants need to be avoided because it is a non-selective killer of leaf tissue.

The other, and even stronger, choice is the 20% vinegar product that is labeled as an organic herbicide. There are at least four commercial companies making this product and it is available in many stores that sell organic products.

There are also several fatty acid products such as Scythe and essential oil products such as PureGro Weed Crush. All these organic herbicides should be sprayed with pump-up, trombone or backpack sprayers – not with hose-end sprayers. You need to do the mixing instead of trusting a cheap device to distribute evenly. My favorite sprayer for homeowners is the Hudson Trombone Sprayer.

Compost broadcast and raked into turf has fertilizer and pre-emergent weed control properties

Shredded native mulch will smother weeds weeds growing on bare soil in beds

After spraying your organic herbicide, it’s ideal to apply a thin layer of compost (½”) to the turf. Compost applied at this time of the year functions as a mild fertilizer and subtle weed preventer. As humic acid is made more bio-available, weed seed are much less likely to germinate. Compost has a longer lasting period of efficacy than corn gluten meal and other pre-emergents.

If winter weeds are growing through gravel, mulch or in cracks and joints in concrete and other paving, spray them as well with vinegar and other organic herbicides. These natural herbicides are not selective, so be careful where you spray. Avoid plants that you don’t want to injure. Weeds growing in beds can also be killed by hand removal or killing them with one of the push-pull hoes. Throwing shredded tree trimmings mulch on top of small emerging weeds will also kill them.

Stirrup and Scuffle hoes for weed control in beds

I’m asked often about corn gluten meal but it has no weed control properties at this time of year. It is a natural pre-emergent product and has to be applied before the weed seeds germinate. Mark your calendars for it to be applied in the fall around September 15 – 30th to stop the cool season weeds and in the early spring around March 15 – 30th to stop summer weeds like grass burs, crabgrass and dallisgrass.