Q. If plants primarily grow at night, does that have implications for foliar sprays — that maybe they should be applied at night?
A. A plant collects energy from the light during the day, while the sun is shining, and stores it so that it has energy to grow at the darkest time of the night, and at dawn. (By the way, how’s that for a parallel to spiritual growth? There are hundreds of beautiful examples like that.)
I used to think that foliar spraying should occur in the evening because plants grow at night, but I don’t think that’s the mechanism anymore. It is true, generally, in most environments, that plants absorb nutrients most effectively at night. But I think that’s a reflection of humidity and dew point. In essence, the longer you can keep a spray droplet liquid on the leaf surface, the more effectively it’s absorbed. So, if you apply in the evening and you have a lower dew point, that droplet remains liquid for a longer period of time than if you applied it in the morning.
From John Kempf’s talk at last summer’s Farm Weird event at Jason Mauck’s farm in Indiana. Hear both John and Jason at this year’s Acres U.S.A. Eco-Ag conference! December 1-4 in Madison, Wisconsin. conference.eco-ag.com
