From Rome Ethredge:
Irrigating Wheat and other Small grains
We know that small grains yield better with a dry sunny spring but we can benefit from irrigation at times, especially during grain fill.
Dr. Wes Porter, UGA, says he normally recommends ET replacement on small grains and this time of year we are at or above .10” to .15″ per day putting us at 0.75 to 1″ per week. And this follows the Univ. of Florida small grains crop water use curve in the 2nd slide below as well. You can get the ET rates from your local UGA weather station.
We need to avoid watering during bloom to keep from making Fusarium Head scab disease worse. Then, follow the ET rates or as a rough guide: 0.75 to 1 inch a week if we don’t get it from rain or snow, lol.
Stop watering when we get to the hard dough stage if we have moisture.