Tuesday, July 17, 2012

Roots, where did they go?

This post is going to be a little more educational in nature.  If you are the type of person that learns visually, just look at the pictures, they say a thousand words.  The optimal growing temperature for cool season grasses (poa, bentgrass - like we have on our greens) is 68 - 77 degrees.  The optimal soil temperature for root growth is 50 - 64 degrees.  Once we get beyond these optimal temps, the plant starts to decline, especially at temps higher than 86 degrees.  At 86 degrees the plant expels more energy than it can take it.  Plants take in food just like we do, its called photosynthesis.  They also "breath" or perform respiration like we do.  When they respire, they expel carbon and normally this carbon is brought in from the atmosphere through photosynthesis, BUT when you have high temps, the plant shuts down photosynthesis.  So where does the carbon come from that is expelled during respiration.... THE ROOTS. 

After all that talk, basically when its hot out, the roots die back.   Above that, poa roots are typically 1-2" in length in the summer, while bentgrass roots are usually 2-8" long.  poa doesn't have a lot to give when the heat takes it.

Can you guess where this is from?

The front of #17 green.  The soil temp is at 99 degrees.

Our current root system on #17 green.

Sorry, this is not ours.  This was on a bentgrass green in Detroit.  Big difference in poa and bentgrass.

I am not writing this to make excuses, just supply some facts.  We are currently on babysitting mode on #17 green.  We have to syringe the green with water about every two hours to keep it from wilting and going backwards on us.  Usually in about mid-September is when the temps really start to cool down and the roots start coming back.