Ask Erik: May/June, 2008
Erik,
There’s a lot of talk at the local hydroponics shop about sprays for plants. How well do these sprays work? It seems odd that plants would feed through the leaves, because that’s why they have roots. What do you think about foliar sprays and do you recommend them?
Thanks, Sammy.
Sammy,
That’s a very good question. Foliar sprays have gained a lot of popularity in the hydroponics industry over the last few years. Various sprays have been applied through conventional agriculture for many decades now. Just like nutrients, supplements, and beneficials applied through the roots, the effectiveness of sprays will be determined by the timing, frequency, and types of products used for the application.
You are absolutely correct in the sense that plants should receive most of their nutritional requirements through the root zone rather than the leaves. But don’t forget that oxygen and carbon dioxide are vital plant elements, and they often pass in and out of the leaves, so it seems nature has created a nutritional gateway of sorts through the plant’s foliage.
Based on reports I have received from a wide variety of growers, there are some benefits to be reaped through carefully timed and formulated foliar applications. I have also seen growing situations where the leaves of the crop had been chemically burnt off with hasty and poorly researched foliar applications.
It is advisable to use products specifically formulated for foliar applications if you are a less-experienced grower or have not had much in the way of hands-on experience with foliar sprays.
A lot of indoor crops get their biggest growth surge during the transitional phase from vegetative to flowering growth. At this time, plants are often using and absorbing nutrients, supplements, and beneficials at the roots faster than can be transported by the plant. At this time a nutrient deficit may occur, even while environmental and nutritional requirements are optimal.
The late vegetative and early flowering phases provide the grower an opportunity to help deliver nutrients to plants immediately when they are needed. Other substances supplied in the foliar spray will further help to amplify natural plant responses such as flowering.
Learn the protocols of foliar spraying. Ask for advice at your local hydroponics shop or research other sources to learn the importance of timing, surfactants, hygiene, equipment, avoiding leaf scald, etc.
So, for colossal results, you can give your plants a foliar blast from time to time. Just make sure that you have thought it out and selected the right formulations.
Cheers, Erik Biksa
