Spring Fertilizer and Pre-emergent Application – This Year It’s Different

The cold weather of January 2014 may have made significant damage on bermudagrass, St. Augustinegrass and centipedegrass lawns.

Though these grasses usually tolerate winter cold in the metro Atlanta area, all can suffer if temperatures drop low enough for long enough.

Fertilizing or applying a pre-emergent too early can weaken grass, even kill it. Pre-emergent chemicals can inhibit new root formation on creeping grasses.  Early fertilization on weak grass can damage it further..

This year, I recommend changing the timing of your application of pre-emergent: instead of applying it all at once sometime between March 1 – 15, apply it at half-strength Mar. 15 with a followup half-strength application in early May.

As for fertilizing, this year it’s important to wait until you’re sure your grass is growing strongly. Typically that means waiting until the soil temperature is consistently 65 degrees at a 4″ depth.

Wondering when that happens? Easy! Go to georgiaweather.net , enter your ZIP code and click on “31 Day Summary”.

For reference, the Dunwoody weather station first recorded 65 degrees at the four inch depth on 4/5/2010, 4/10/2011, 3/18/2012 and 4/16/2013. For metro Atlanta, let’s round it down to 4/1 so we can all remember it: Fertilize warm season grasses the week after April Fool’s Day.

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map of Georgia Automated Environmental Monitoring Network

map of Georgia Automated Environmental Monitoring Network