Sunday, August 7, 2016

How To Kill Crabgrass and Not the Entire Yard

Crabgrass (Digitaria sanguinalis) plants can produce 150,000 seeds per plant
and can take over a lawn in just a couple years!
From the Garden Counselor

Kill Crabgrass Now! Don’t delay, but don't make a mistake.
The innocent looking, attractive green seedlings quickly become voracious monsters that can devour your entire lawn. What will it cost in terms of time, energy and money to get rid of this nuisance? Unfortunately, this is one of the worst weeds to get rid of.
The fast way to kill crabgrass could also be a fast way to kill your good lawn grass. Many lawns will tolerate a chemical spray designed to kill crabgrass, but not all grass varieties are safe. Many different manufacturers of garden chemicals offer their own version of crabgrass killer.
It is VERY IMPORTANT to read the label on Crabgrass Killer.
Why? Crabgrass killer will kill some varieties of grass lawns, under any conditions. It will kill other varieties if used incorrectly. To borrow a famous phrase: It will kill some of the grass all of the time, and all of the grass some of the time!
Another article on St. Augustine lawns and centipede grass tells how they are particularly susceptible to most crabgrass killers. They are likely to suffer injury, and may be killed. Some products may permit their use on these grasses at lower concentrations, others say not at all. Bermuda, zoysia and bent grass may be fine for applications of crabgrass killer, but not at all times of the year. Fescues and ryegrass may be alright with some products, or some concentrations, but not all.
As an example, a convenient, Ready-To-Spray product for Fescue, Kentucky Bluegrass, or Perennial Ryegrass Lawns ONLY. It does not kill any broadleaf weeds, with a very specific active ingredient, Fenoxaprop-p-ethyl, which targets grass species. Just make sure your lawn grass variety is safe.
You can successfully kill crabgrass in some lawns with products designed for that purpose. This should be marked clearly on the label. They are available as concentrates that can be mixed in a tank sprayer. Use no more than the recommended amount.
Trying to kill crabgrass in your lawn when the weather is extremely hot will place additional stress on your good grass. If you spray when the temperature is over 85 degrees, the lawn can incur more damage than if you spray when it is cooler.It is best to wait for a cooler spell, if possible. If that is not likely to happen, then spray very early in the morning or later in the evening, avoiding the hottest part of the day. It is always better to do a repeat application than to use a stronger mix, thinking it will work better or faster.
Do not use these concentrates in a hose end sprayer unless it is the type that allows you to dial in the setting for the correct concentration. The liquid fertilizer sprayers do not permit this. Products are also found in a Ready-To-Use bottle for spot treatments and small areas. Be careful with these versions. Some spot treatment products may not be designed for use in a lawn. If the label says “non-selective”, it will kill anything it contacts. You want to use a “selective” killer intended to specifically kill crabgrass in a lawn.
If the crabgrass you are spraying is young, it may die after one treatment. More mature weeds may require one or two repeat applications. Follow the interval schedule on the label for the repeat time.
  • Don’t mow the lawn prior to applying the chemical, since you want more leaf area of the weed to soak up the spray.
  • Don’t water after spraying for 24 hours, and if rain is forecast, it may be better to wait and apply the treatment after the storm.
  • Don't ruin your spray equipment. Thoroughly rinse the container immediately after use. Avoid leaving residue that could clog the unit or affect plants later.
  • Don’t mix more product than you will use in one application. Potency can diminish if the mix sits for days before it is used.
It is not uncommon for a lawn to show discoloring after being sprayed with chemicals for killing crabgrass. This should not be a cause for concern, if you used the appropriate dosage.
If you see yellowing of your lawn, just be patient, and the lawn should grow out to its normal color within one or two mowings.
With the Tenacity product, only the affected weeds stop producing chlorophyll and start to turn white as they die. 

No comments: