LEXINGTON, Ky. — After a warmer-than-normal early spring promoted early plant growth, the expected dip back down to colder temperatures came last week, putting many plant lovers on guard.

But the real damage could take place in the state’s wheat crop, which had advanced beyond a normal growth stage with the warm winter and early spring. A cold spell at this stage could have left damage to the biggest wheat crop planted here in the last few years.

The USDA National Agricultural Statistics Service’s Kentucky office reported this year’s winter wheat crop represented the largest seeding since 2008, at 580,000 acres. Jim Herbek, grain crop specialist with the University of Kentucky (UK) College of Agriculture, said in a recent edition of Wheat Science News the crop is at least 2-3 weeks ahead of normal.

“Wheat damage from cold temperatures depends on the wheat growth stage, the critical temperature needed for damage at each growth stage and duration of the critical temperature (at least two hours are needed),” he wrote.

That critical temperature may have been seen in some wheat fields. Chad Lee, a UK extension agronomist, said some temperatures were reported below the 30-degree mark.

“Those thermometers were in the field and not weather stations,” he said. Lee added, according to general guidelines, if temperatures get below 30 degrees for two hours or more and the wheat heads are out, then one can sustain severe damage to those plants.

“What we don’t really know on a field-by-field basis is how low the temperatures really got and how long it stayed low,” he said. “The second thing is, you really can’t do a good job of assessing damage until about a week to 10 days after the freeze event occurred. We just need that many days of good growing conditions and good weather to see how the crop is going to respond.”

Lee pointed out about half the wheat crop was at the heading or flowering stage, a critical point when the freezing temperatures occurred.

Wheat producers are likely to recall the 2007 crop, when similar weather conditions were seen – with one exception. This year’s freeze lasted only a couple of days; the 2007 event lasted five days, creating extensive damage to portions of the crop that year.

Lee suggests producers walk through their fields in about a week to see how their crop is responding. “If there is damage on the primary heads, then look at the secondary tillers to see if those are still developing and have the potential to produce any heads,” he said.

At this point, he is not overly concerned there will be any major damage. “Certainly we have the potential to have lost some yield, but we don’t have any idea what that extent might be until we get out there and do some scouting,” he said.

Tom Priddy, a UK ag meteorologist, said temperatures in the last cold spell were more normal for this time of year than those associated with the warm weather the state has recently experienced, and it would not be out of the question to have another cold morning or two.

“We’ve seen some of these frosts go all the way up until the end of April and the beginning of May before, so now the question is, is it going to happen again?” he asked.

Priddy added there is no indication of a longer freeze event coming, like the one five years ago, but there were indeed some valley readings in the 20s last week. If there is something to think about weather-wise, it may be the fact that more than one-third of the state is classified as being abnormally dry and longer-range forecasts are beginning to shift away from the above-normal precipitation forecast previously expected.

With planting season here, a little rain would be helpful, Priddy emphasized. “We want to progress the planting season along, but we’d like to have a rain; an inch of rain a week to get things established, and we’re really not seeing that right now and that’s got everybody concerned,” he said.