Checking plant populations on late-March planted soybeans, two things surprised me recently.

First, the stand was a respectable 126,000 plants per acre, according to the hula-hoop method, averaged over 7 spots within the 15 acre field. Purdue University Extension specialist Shaun Casteel says that's more than enough plants to produce top yield.

Second, a bright purple bloom stared at me when I brushed over a plant. The soybeans were beginning to bloom. When I checked them, it was the last days of May. Many other things are running three to four weeks ahead of normal that are controlled primarily by heat unit accumulation.

EARLY FLOWER: This picture, taken on Memorial Day, once known as decoration day, shows this soybean wanted to be dressed up for the occasion, with a decoration of its' own. Early flowering is complicated.

Corn rootworms hatched earlier than at any time in the last 35 years, and by about 10 days earlier than the previous record early hatch. Lightning bugs were spotted before Memorial Day. Cherries were ripe and baked into pies before the end of May. The rub is that soybeans are supposed to be controlled more by day length than heat unit accumulation.

Casteel confirms that is the case, although technically he says it's the night length that triggers blooming. It varies from maturity group and variety to variety. Heat units can have an effect, but photoperiod response if the main driver. So what's going on with these early bloomers. Casteel says they had enough growth when night length reached their trigger, say 9 hours for discussion purposes, that they began to flower.

At some point, as the night grows very short near June 21, they will actually stop flowering, he says. Then as the night lengthens again and they get back to their trigger, in this case 9 hours, they will start blooming again. The net result may be pods at the bottom of the plant from the blooms that came out early, a couple of nodes with no pods as tall, and then pods again once the plants began flowering again.

Whether this whole process is good or bad depends upon weather conditions. It may not affect yield at all, it could actually clip yield some, or it may add a bit to yield, all depending upon weather conditions and timing, Casteel says. If the plants have enough moisture when the early blooms are out, they will retain them. If not they may abort them. But they will bloom again once they move back closer to their photoperiod trigger.

It's nothing to be alarmed about. Soybeans were simply planted so early that they were tricked into flowering ahead of schedule, on the front side of the night length trigger. They will stop flowering, grow again, then flower again on the back side of the trigger as nights actually lengthen again.