Many White County residents woke up to a sight last week that they would rather not see in the springtime: a blanket of snow. While the snow and the freezing temperatures it brought left relatively quickly, will we see any lasting effects on our plants this spring? For the most part, we may have been saved by the cold nighttime temperatures we had in the weeks leading up to our frost/freeze event.
Many things, including the few crops that farmers had planted, were not out of the ground yet due to cold soils. One unfortunate victim may be our flowering shrubs, such as redbuds, crabapples, and magnolias which were in full show before the freeze event. It may not be surprising if we lose some of those flowers earlier than we had hoped. As long as these trees/shrubs were healthy heading into the season, however, they should regroup and be just fine in the coming summer, just don’t be alarmed if they look rough for a little while. It is important to remember that in most years, Indiana is not out of our freeze window until the last week or so of April, so last week’s weather was not unprecedented. Most plants we grow in this zone will adjust just fine. We likely would have been in much more trouble had the warm spell in early April continued, but since it subsided, most of our plants were still in their budding stage. One thing we may keep an eye on is the availability of local tree fruit crops. As temperatures reach around 28 F, fruit growers with trees that are flowering can begin to expect a loss, though it should still be minimal. At 25 F they can expect a loss by as much as 90% depending on how far along development was. Hopefully, our orchards around the state did not reach those levels.
From an agronomic standpoint, should any corn be out of the ground, farmers may keep an eye on it. According to Purdue Extension Corn Specialist Bob Nielsen, “The effect of frost on young corn when it is accompanied by temperatures no lower than about 30F is primarily damage and death of the exposed above ground leaf tissue. As long as the growing point of the young plant (aka the apical meristem) is still protected below the soil surface, the injured plant usually recovers from the effects of the superficial leaf damage. Within 3 to 5 days of the frost event (more quickly with warm temperatures, more slowly if cool), elongation of the undamaged leaf tissue in the whorl will become evident. As long as the recovery is vigorous, subsequent stand establishment should be not be affected. Injury to the crop can look very serious the day after the event or even two days after the event, but recovery is likely if there is no injury to the growing points of the affected plants.” The three-to-five day window after a freeze event is also crucial to soybeans. Surviving soybean plants will show new leaves emerging from one or both nodes at the cotyledons, while dead plants will still look dead. If recovery is evident after three to five days, then replanting is not justified. If a significant proportion of the population is obviously dead after this same period of time, then replanting may be justified.