Tuesday, March 18, 2014

When To Fertilize?

As the temperatures begin to rise and Spring is in the air, its only natural to start thinking about outdoor projects - which usually include tackling that lawn that was neglected all winter long. 
This article was provided to us by Russell Landscape and was written by Clint Waltz, a PhD and Turfgrass Specialist at UGA.  It provides great insight as to when the best time to fertilize your lawn may be. If you have any additional questions, be sure to contact your local garden store or your professional landscape company.

Spring Timing for Warm-season Turfgrass Fertilization
Clint Waltz, Ph.D., Turfgrass Specialist, The University of Georgia 
This time of year we start seeing marketing and commercials promoting “now” is the time to fertilize lawns. Homeowners need to know the proper timing for the spring nitrogen application to warm-season grasses like bermudagrass and zoysiagrass.  Remember that nitrogen (N) is the first number on a fertilizer bag.  Simply, nitrogen should not be applied to warm-season grasses until the soil temperatures at the 4-inch depth are consistently 65° F and rising.  For areas north of Atlanta these environmental conditions may not occur until mid-April.  Also, waiting on proper soil temperatures allows the grass to green-up on its own, typically better than forcing the grass to green-up too soon. 

Four reasons for withholding nitrogen until late spring include:

1.      Good Agronomics – when soil temperatures are below 65° F there is little, to no, root activity for warm-season grasses.  Why apply nitrogen when the grass cannot use it?

2.      Environmental – if not taken-up by the plant, nitrogen can leach through the soil or be lost by runoff.  Why apply nitrogen when the grass cannot take it up and risk contaminating water bodies?

3.      Pest Management – nitrogen fertilization during green-up can make the grass more susceptible to diseases, insects, and open voids in the canopy for weeds to establish.  Why apply nitrogen at a time when the grass is more sensitive to pests?

4.      Economic – when a nitrogen application is mistimed it can be inefficient and costly.  Why spend the money on nitrogen when the grass roots cannot take it up, it can move out of the root zone becoming an environmental hazard, or lead to pest issues that become an additional cost to treat?

To determine if environmental conditions are favorable for spring nitrogen, monitor soil temperatures in your own lawn with a 4- to 6-inch soil thermometer or, visit www.GeorgiaWeather.net to get local environmental conditions.

If your lawn is a combination of bermudagrass and tall fescue, a cool-season species, the two areas in the lawn should be fertilized independently and when the environmental conditions are ideal for each species.  Late February or early March is good for tall fescue but not bermudagrass and zoysiagrass.

Following these simple guidelines for warm-season grasses can lead to healthier lawns, reduced environmental impacts, and less cost. 

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