FROSTED! Corn Recovery Prospects Better Than Wheat And Barley

Frosted freshly-emerged corn needs time to recover; Watch wheat and barley for damage.

Published on: May 15, 2013

Monday night's widespread frost across central Pennsylvania nipped a lot of just-emerged corn. By mid-morning Tuesday, those tender green shoots were laying down and turning black.

But don't launch into your replant mode just yet, says Greg Roth, Penn State University Extension corn agronomist. Normally corn in the V2 to V3 stage can recover well from this type of frost.

The standard recommendation for assessing damage to frost damaged fields is to come back three to four days later and assess the survival, then decide on replanting options. "We've seen as much as three nights of successive frost, and plants were able to recover well," reflects Roth.

NOT A GONER: Frost injury at this stage usually isnt lethal. Give the plant four to five warm growing days to recover, then look for signs of fresh regrowth. (Purdue University photo)
NOT A 'GONER': Frost injury at this stage usually isn't lethal. Give the plant four to five warm growing days to recover, then look for signs of fresh regrowth. (Purdue University photo)

Due to the late spring, few if any fields of corn in the Northeast have advanced to the V4 to V5 stage. Such fields are more likely to experience stand losses that warrant replanting.

So the standing recommendation holds: Wait several days before considering replanting, then assess the damage and make a replant decision accordingly.

The growing point region of a corn plant remains below ground until about the 5-leaf collar stage, adds Bob Nielsen, Roth's counterpart at Purdue University. It's reasonably protected from the effects of above ground frost. Consequently, the effects of "simple" frost damage to corn are usually minor and limited to death of aboveground plant parts. Corn can easily recover from this type of damage early in its development and suffer no yield loss whatsoever.

When air temperatures actually drop to lethal levels (28 degrees Fahrenheit or less) for more than a few hours, the growing point region of a young corn plant can be injured or killed even if it is still below the soil surface. But it's a rare occurrence. The distinction between damage by frost and lethal temperatures is why your experience with frost damage in the past may differ from your neighbor's.

Recognize that cool days following a frost event may slow plant recovery and delay your ability to assess their health.

Every decision that you make influences the size and scope for corn yields. From the corn hybrid you select to the seeding rate and row width you choose. Download our FREE report over Maximizing Your Corn Yield.

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Best recommendation: Continue planting the remainder of your crop acres, says Nielsen. After four to five days, surviving corn plants should be showing new leaf tissue expanding from the whorls. The dead tissue of the damaged part of the whorl may restrict this leaf extension for a while. But in most cases it won't restrict it completely.

About your wheat and barley . . .
Generally more than 2 hours of exposure to 28 F temperatures in the boot stage or 30 F in the heading stage is required to cause injury. Some areas received that, notes Roth.

Frost injury symptoms may be difficult to diagnose for a few days or a week. One symptom of minor injury you may see would be heads having difficulty emerging from the boot.

In more severe cases white or discolored heads may be evident. In the worst cases, complete head sterility is common. This Kansas State publication provides some detailed scouting guidelines for diagnosing the impacts of freeze damage on wheat.

Often the heads appear normal even though the anthers are dead. Anthers are more sensitive to freeze damage than other plant parts. Carefully examine the anthers. If they're white and desiccated instead of their normal light green or yellow color, they may not produce grain.

Late this week or early next, determine how much damage has occurred for both crop insurance assessment and the potential to salvage damaged crops for forage.

Every decision that you make influences the size and scope for corn yields. From the corn hybrid you select to the seeding rate and row width you choose. Download our FREE report over Maximizing Your Corn Yield.