How Heavy Rain in Middle TN Affects Your Fertilizer Application

Springtime in Middle Tennessee is notorious for its unpredictable weather. It is not uncommon to have a beautiful, sunny morning followed by a torrential, flooding downpour in the afternoon. For homeowners who have just had their lawn treated, a sudden heavy rainstorm often causes panic. The immediate fear is: "Did all that expensive fertilizer and weed control just wash down the storm drain?"

Fortunately, modern professional lawn care products are designed to withstand the elements far better than the products available at the local hardware store. Here is how heavy rain actually affects your lawn treatments.

Granular Fertilizers: Rain is Usually Good
Most of the fertilizers and pre-emergents we apply at Mr. Lawn Care are granular. These products actually require moisture to activate. Water breaks down the granule, allowing the nutrients or the pre-emergent barrier to move down into the soil profile where the roots can access them. A moderate to heavy rain shortly after a granular application is often ideal. The only time rain becomes a problem for granular products is in the event of severe, rushing floodwaters that physically erode the topsoil and wash the granules away before they can dissolve.

Liquid Weed Control: The Drying Window
Liquid post-emergent weed controls (the products used to kill existing broadleaf weeds) work differently. These products need to be absorbed through the leaf tissue of the weed. Therefore, they require a "drying window" to bond to the plant. In typical Middle Tennessee temperatures, this takes about 1 to 2 hours. Once the liquid has dried on the leaf, it becomes rainfast. If a heavy rain occurs three hours after a liquid application, the treatment will still be highly effective. If it downpours 15 minutes after we spray, the product may be diluted, and a re-treatment might be necessary.

Our Weather Protocol
At Mr. Lawn Care, we constantly monitor local radar. If we know a heavy storm is imminent within the hour, we will pause liquid applications to ensure effectiveness. If you ever experience a massive downpour immediately following a liquid treatment and notice the weeds aren't curling after 10-14 days, simply let us know. We always stand behind our work and will address any weather-related washouts promptly.