Renewable Farming

Foliar-sprayed WakeUP can help protect early-planted beans from frost damage

Two weeks of field-grade weather across the Upper Midwest allowed farmers record planting progress for corn and soybeans. Memories of rain delays the past two seasons motivated growers to keep planters rolling as long as they could stay awake. With 24-row and larger planters plus precision GPS guidance, growers can cover acres fast. USDA’s crop progress report for May 3 shows Iowa’s corn is 78% planted, up from 39% last week and far above the 5-year average of 46%. Iowa’s soybeans are 46% planted, a dramatic acceleration above the 5-year average of 9% for this date.

May 4, 2020 — One north central Iowa client tells us he finished 1,500 acres of corn and beans April 29. His soybeans were “mole-hilling” early this week. Now he’s anxious about the 10-day forecast showing overnight lows well below freezing this weekend. The first true leaves will have emerged, a vulnerable point for beans.  Corn can survive frost damage if the growing point is still safe below ground. 

This is how young soybeans looked Oct. 5, 2010, after a freeze
the night of Oct. 4. Beans sprayed with WakeUP survived
two subfreezing nights.

Here’s some evidence showing how WakeUP could offer two or three degrees of freeze protection for soybeans. Our small experiment  was almost 10 years ago. After harvesting sweetcorn, we seeded oats as a cover, and planted soybeans with the intent of spraying beans with WakeUP for a frost-protection experiment. You can read our results on the reprint of our 2010 report, inserted below.

This little test in fall 2010 verified a large field trial early that spring, when a grower sprayed WakeUP plus a tank-mixed pound of sugar per acre on soybeans at the first two trifoliate leaves. After a sharp frost, his beans looked somewhat wilted, but rebounded. That fall, his WakeUP-sprayed field outyielded his other bean fields which were planted later. 

We’ve known for years that WakeUP accelerates sugar transport through the phloem circulation systems of crops. Stems and roots especially gain sugar levels after foliar spraying with WakeUP. That’s easily verified with brix tests. Apparently, WakeUP’s formulation — entirely plant-based — reduces internal surface tension of plant sap, so sugar solutions manufactured by leaves flow more easily through phloem tubes.  (For more information on WakeUP, call or e-mail us.)

Adding some sugar in a foliar spray probably provides an extra touch of freeze resistance. WakeUP allows dissolved sugar in spray water to penetrate quickly into plant metabolism. Another “warming” benefit could be occurring in the days after spraying: Extra sugar that’s exuded from roots of WakeUP-sprayed crops enhances microbe multiplication around roots. Actually, spraying WakeUP at V2 on corn and soybeans has long been our standard recommendation to build strong, early roots with a rich population of beneficial mycorrhiza.

In recent years, soybean growers have tended to plant beans earlier so the plants form shorter internodes, thus more opportunities for pods. But earlier emergence also creates more frost risk. 

This is a reprint of a PDF report we did almost 10 years ago.