Tree frost (BlackburnNews.com photo by Ray Baynton)

Watching For Frost

Frost is the next thing to be aware of with the later than normal planting window.

According to OMAFRA, some corn growers have been monitoring their corn growth stages and asking about gauging the risks associated with corn maturity and frost.

A light frost at 0°C may damage or kill leaves but not be cold enough, or last long enough, to penetrate into the stem and kill the plant. While premature leaf death limits further grain fill from photosynthesis, a living stem can still trans-locate dry matter to the developing grain to continue to provide some grain fill after a light frost event.

Temperatures that are low enough, for example -2°C, can penetrate and kill the entire plant.

Yields can be affected by frost depending on the stage of the plant.

Any frost event during the blister or milk stage would result in significant grain yield losses as significant grain fill is still yet to occur at these stages.

A light frost event at the dough stage may reduce yields by 35% while a killing frost may reduce yields by 55%.

Yield loss in the dent stage depends on the relative time left to mature and may reduce yields by 25% while a killing frost may reduce yields by 40%.

And during the mid-dent stage light and killing frosts may reduce yields around 5% and 10% respectively.