Texas Lawns: Pre-Emergent Weed Control
Fall is the Time to Treat Lawns to Stop Weeds Before They Begin
Sep 12, 2009
Because many weeds grow and strengthen while grass is dormant, pre-emergent weed control is important for Texas lawns. A pre-emergent weed control must be done before the weeds are growing. So, the best times to treat lawn weeds with a pre-emergent herbicide are mid-September and mid-March.
Common Weeds in Texas Lawns
Even the best maintained and healthy lawns can get weeds. However an over-abundance of weeds usually reflects grass that is not healthy enough to ward off invaders. The two main types of weeds are grassy weeds like crabgrass and broadleaf weeds such as dandelions.
The most common weeds that grow in Texas lawns are: chickweed, clover, crabgrass, dandelions, grassburs, Johnson grass, and nutsedge. Make no mistake; these weeds are hardy and tenacious. Weeds compete with grass for water and nutrients and many times they win the battle.
Pre-emergent Weed Control Products for Texas Lawns
Pre-emergent weed control products are usually granules distributed with a spreader. Because these herbicides are intended to stop weed seeds from growing, they are generally safe to use around established trees and shrubs. However, they should not be spread in areas that the gardener will be planting with seeds in the following months.
According to the Missouri Botanical Garden website, “Team® is one of the more cost effective pre-emergent crabgrass controls. It is a combination of Treflan (active ingredient trifluralin) and Balan (active ingredient benefin). This “team” product gives good early control with the Balan and longer acting control with the Treflan.”
Team® can be found in several commercially available weed control products and is effective on grassy weeds including crabgrass. Options to Team include: Pendelum®, Dimension®, and Cavalcade.
How to Apply Pre-Emergent Weed Control
A pre-emergent herbicide kills seeds as they germinate so that they never grow into weeds. Because some pre-emergent herbicides are less effective or may even damage certain types of lawn grass, it is essential to read the package directions first to make sure that a product is appropriate for the type of lawn grass being treated.
Pre-emergent herbicides for home lawns are most readily available in granular form and can be applied with a fertilizer spreader. To achieve good coverage, apply half the granules while walking one direction across the lawn, and the other half walking perpendicular. Be sure to thoroughly wash the spreader after applying.
"Once the herbicide is applied, then water the application in very thoroughly. It takes approximately 0.5 inches of supplemental irrigation to move the herbicide down in contact with the top layer of the soil where most of the weed seed are germinating," according to James McAfee writing for Agricultural Communications from Texas A&M University System.
Note: pre-emergent herbicides are not effective against weeds that are already growing.
Environmental and health note: these products may cause eye or skin irritation. So wearing gloves and goggles should be considered. Inhaling the per-emergent dust may irritate the respiratory system. Pre-emergent herbicides are toxic to fish. Use caution to avoid runoff into any lake, stream or pond.
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