Better Trees Start at the Root

By Ronda Payne

Growers spend a lifetime in agriculture finding ways to make their trees grow stronger, healthier, more productive, but perhaps it’s time to go back to the beginning; to the seedling and how its roots formed. New research results show that the right seedling propagation trays can make a big impact on root structures and therefore the lifelong health of trees.

In 2013, Darby McGrath, vice-president, research and development with Vineland Research and Innovation Centre started looking at root development. She wanted to know what stage of tree life the barriers and deformities that impact growth, health and strength began.

Her curiosity meshes with Craig Willet’s. As the manager of Ellepot from A.M.A. Horticulture (and a previous nursery operator) he knew growers could benefit from better propagation trays.

“If the roots go everywhere, it makes that tree much more stable in the ground,” says Willet. “It takes up more nutrients and water than if it just had that one tap root.”

Tap roots form (instead of a rounded, radial ball of roots) when they meet a lot of obstructions at the seedling growth stage. Air pruning without obstructions promote healthy roots. The theory of some is to trim the roots back in order to correct deformed growing and encourage the radial structure, but he says this approach is ineffective.

“As a grower, I would have to say that air pruning is the best. The trees are programmed at birth,” he explains. “Even if you cut [the root] it will continue to grow the way it did as a seedling. It’s in its DNA.”

The first prototypes of RootSmart open-wall propagation trays were created in 2015 by A.M.A Horticulture. The trays are able to incorporate the organization’s air pruning Ellepots. In 2017, five years of in-field testing began at Vineland Research and Innovation Centre to see if the trays had the desired impact. Each year, the Vineland team dug up a row of trees to examine root systems. The propagation trays began selling in 2017.

“It is the only one in the market with the least amount of touch points,” Willet says of the trays. “The only touch points are three cones underneath where a root could possibly deflect. The Ellepot is suspended in the air.”

The researchers for the Vineland trial found the RootSmart tray led to higher-quality, better distributed root systems than trees planted with one of the three other types of propagation trays tested.

The need for root development is even more important now as growers face increased weather impacts. Without proper root structure, trees and even blueberry bushes could take longer to get to peak yields, face increased stress, or may even be wiped out as was the case for a California pistachio grower.

“It takes 25 years before you really start to get a decent harvest out of your pistachio trees,” he says. “A strong wind came through and blew them all over. They had poor root structures.”

While fruit trees are seldom in the ground as long as a pistachio tree, having proper radial root systems lead to more production faster and better fruit in the long run. Stronger roots give trees the ability to source nutrients and water from a greater area giving them more of a fighting chance in high heat and dry periods and more stability in flash flooding or high winds.

“We want to educate the growers that there’s something available that will produce a really good tree that will last in the environment,” Willet says.

He adds that at the time they started the trials, there were other options available as people have been studying the problem for decades. Some types of propagation tray systems still have numerous contact points, high prices or awkward shapes that make management difficult.

“There’s a wire racking system that could be purchased to enable the grower to move large numbers of trays with a fork lift,” he notes. 