The earlier and warmer spring temperatures we have been seeing the last few years in Indiana are continuing this year. See Figure 1. What we see is that for each year in the past 15 years temperatures have warmed up earlier than the long term average. Luckily only one year over this period was extremely early and you’ll remember how that ended! In 2012 we started having warm days in mid March and so crop started leafing out and flowering. The inevitable happened and a freeze occurred resulting in widespread damage to many fruit crops and the worst apple crop seen in 70 years in the state. The problem wasn’t so much the time of the freeze but that crops were at an advanced, and sensitive, stage of development when the freeze occurred.
This year is still on the early side with apples in Lafayette around tight cluster. Recent freezes were of short duration and because flowers were still at tight cluster they were too sensitive to the cold. I haven’t seen any widespread freeze damage so far. Yes I say “so far” because we’re not out of the woods yet.
Figure 1. Temperatures in Lafayette, IN. Temperatures are expressed as Growing degree Days (GDD) with a base of 50F. We assume that trees don’t develop below 50F so track the temperatures above this baseline.