FAQ: should you care about air root pruning?

Paul Greenley travels the U.S. talking with growers and helping them get the very best out of their plants. One of the things he gets asked a lot is what air pruning is, how it can help and how it should be done properly. We asked him a few questions to help get to the bottom of what air pruning really is all about.

First off: what is air root pruning and how does it work?

When a root hits relatively dry air, its tip is desiccated or killed. This root loses its dominance and many secondary roots develop to replace it. These are then in turn air pruned and replaced by even more roots, ultimately providing a very large quantity of young vigorous roots without defective roots developing.

Why do roots need air pruning in the first place?

Simply: excellent roots make excellent plants. The plant develops quicker, reaches desired caliper quicker and is generally healthier once transplanted. For trees, good quality, non-girdling roots are vital, as a circled root remains circling once planted out meaning an unstable (and potentially dangerous) tree.

Killing roots sounds bad for the plant – is this really a good thing?

Only the root tips are killed, which forces the plant to rethink where it gets sustenance from. That means it puts out even more lateral roots along the root ball, which is very good for the plant indeed.

How do these containers prune the roots? How much effort does this require?

No effort at all: the container does all the hard work. Most air pruning containers work by having holes in the base of the cell that roots can escape from. The more effective containers air prune up the sides too. This is not the entire solution, however. Roots positively hate being in dry air and will actively avoid it, so that’s why Proptek containers have ribs which direct the roots to the air pruning windows. Because our containers are made from injection-molded plastic it allows us to build in the features that force roots out into the air at both the base and up the sides of the container.

What are the other benefits of air pruning containers?

As containers have holes in them, the media gets exceptional aeration and drainage. Increased oxygen means more roots develop, improving the root to shoot ratio. Waterlogging also becomes less of a problem. An injection molded container also lends itself to mechanization better, ensuring an efficient operation. Something I see all too often is manual shaving of the root ball of every plant leaving the nursery to get rid of circling roots – a sure sign poor quality containers were used. Ensuring you have a long-lasting air pruning container that forcibly trains the roots out of the windows eradicates this arduous task.

There’s the green aspect too – Proptek air pruning containers offer sustainability and will last for many years, thereby producing excellent roots year after year

Are there any downsides to air pruning containers?

Not so much downsides, but there are things to consider. As drainage is improved over a simpler container, watering cycles and fertilizing need adjusting. A little less more often is usually the case. At Proptek, we have tried and tested many designs of container and window configurations and worked closely with growers to ensure the perfect balance between drying out effectively and drying out too quickly.

Let’s talk bottom line: Can air pruning actually make me more money?

In addition to better plants, our experiences show it can and does make growers more money. This is by helping to turn around plants quicker as well as higher survivability rates, but also by saving money on manual labor costs through mechanization. Growers’ customers are often happier too that they’ve received a better plant, ensuring repeat business. Every set up is different, so we recommend giving us a call to determine what can be achieved.

Paul Greenley is the sales manager for Proptek. You can reach him at [email protected].