Ann Parker, Master Gardener
A weed is a plant located where it is not wanted. Have you spent too many hours down on your knees pulling weeds or repetitively spraying weed-killers? Pre-emergents are a group of lawn products that offer relief from countless hours of handpicking weeds. It is not an instant fix, but diligence at putting these products on your lawn can pay off in the long run.
Typically, applications should occur early spring (February-March) before warm season weeds appear and in the fall for cool season weeds (August-September). Early this summer, I was surprised when a trusted nursery owner told me that I should be applying a pre-emergent every three months due to our temperate climate. I’m not certain that four applications are necessary each year but now think that an early summer application is in order.
It is imperative to check the label before buying a pre-emergent to ensure that your weeds are listed. If not, keep looking! The product is applied before the weeds sprout through the soil and require activation, usually within a couple of days, by irrigation or rainfall. One half inch of precipitation is adequate. Pre-emergent herbicides are chemicals and many people prefer to avoid them. Organic varieties are available, but be aware that they are more costly and shorter-lived than chemical types.
Many combination products are included in “weed and feed” products for turf. These are available throughout Texas but are not useful. The reason being that when it is time for application of herbicides before weed germination in the spring, it is not time for fertilization. Fertilize when the grass is fully greened up.
For best results after applying the herbicides, avoid mowing for three to four days. This will allow enough plant material to intercept the chemical and give it time to move throughout the plant.
The best way to control weeds in your lawn is by proper turf management including thorough and prescribed watering, judicious fertilization and proper mowing. And, perseverance in correct use of pre-emergent herbicides can help you attain that healthy stand of turf.