Benefits of Applying a Pre-Emerge to Your Lawn
I am often asked the question, “Why do you start spraying so early?”
This a good question because it seems like there is nothing going on in your lawn in the late winter, but I can assure you there is. As the temperature of the soil begins to warm up ever so slightly, the seeds of weeds that are in your lawn begin to try to grow. Different plants prefer different temperatures. The reason we begin applying pre-emergent early, is to have it down before these weed seeds try to grow. If we do that, then we can be very effective in keeping weeds out of your lawn.
Another part to this question is how long the pre-emergent will stay active. Meaning, how long will it keep weeds from germinating. This depends on the product being used. Some products have a very long residual and some are very short. Most products when applied in January or February will not last throughout the growing season. This is why we split our application of pre emergent into 2 separate treatments.
If we tried to get it all the pre emergent down at one application, we would either be too early to have season long control. Or, the application would be too late and crabgrass, dallisgrass, or other summer annuals would have already germinated.
In West Tennessee, the weather is so unpredictable that the only way to get really effective weed control is to split the pre-emergent application into 2 separate treatments. That way, the lawn is protected from early germinating weeds and we get season long control.