There's a chill in the air

Reports are starting to come in from various spots in the province where the thermometer dipped below zero on Saturday morning. For corn fields, especially those planted a little later, that’s not good news.
I spoke to OMAFRA corn lead Greg Stewart this morning and he says the early dent stage is the cut-off point at which corn can tolerate a frost without much of a yield penalty. Otherwise, frost that kills leaves also shuts off photosynthesis and the flow of nutrients to the cob. But as long as the temperature wasn’t below -2C the stalk will remain viable and keep pushing some nutrients into the ear. Anything colder than that will kill the plant and it will start to black layer.
How much of a yield hit can you expect? The worst scenario has the plant shut down at mid-dough. That’ll cost you about 40 per cent. At early dent it’s about 25 per cent. If only the leaves are frost-killed at mid-dough there’s also a 25 per cent yield hit.
In any case, Stewart says that if your field hasn’t made it to early dent when it gets a taste of frost you won’t be too happy with the resulting yield and grain quality. Those fields that just got a bit chilly but escaped frost damage should resume normal photosynthesis as soon as the weather warms up again.
But it looks like at least some fields – both corn and beans - in Wellington and a few on the sands further south may have been damaged on Saturday.
Stewart says he’ll know the extent of the damage in a couple of days.
The weatherman is definitely not on our side this year.