he term air-prune is a pretty simple concept. On the microscopic level it is more complicated, but I will leave that explanation to the scientists and PhDs. The term air-prune just means that the root-tip of a plant has been “burned off” or “dried out,” causing the plant to produce new roots. When this happens the plant has more opportunities to uptake food and nutrients, which is going to allow the plant to be healthier, stronger and better producing.
The way in which air-pruning happens is pretty simple. The process is automatic and natural. Think about what happens when the top of a plant is pruned to promote lateral growth. When air-pruning happens, lateral growth of the roots is the result.
Air-pruning occurs when a plant’s roots reach the side of the aeration container. In quality aeration containers, the root tip will come in contact with the air and the pruning occurs. This action will cause more roots to grow and the process will occur again and again, filling up the container with roots and root tips. When growing one-season annuals, this better root structure means more flowers and fruits.
Is air-pruning a good thing? This is a question that has been asked many times, especially early on when aeration containers started surfacing in the hobby market. It was a new idea that most home gardeners had never heard of, or if they had, they never thought about it.
The easiest and best answer to the question is, yes! An air-pruned root structure is going to produce a better plant than a root-bound plant growing in containers that trap roots and promote root circling, not root pruning. This has been shown in university studies across the country.
In my opinion, every plant benefits from air-pruning, but there are differences in each species as to how many roots and how the root structure forms. There may be species out there that I do not know of, but my experience in the field has lead me to believe that all plants will benefit from air-pruning.
Keep in mind that for this purpose, my definition of a plant is something with roots. I am not considering slime or algae or anything like that in this conversation. A better way to answer the question, “Does air-pruning work for all kinds of plants?” might be to ask, “How best can air-pruning benefit plants?”
When used as a production tool, a quality aeration container can help farmers eliminate steps in the growing operation, thus speeding up production and helping them grow more trees and shrubs faster. Stated earlier, air-pruning helps one-season annuals produce more flowers and fruits, but in tree and shrub production it helps the tree farmer grow better plants, which improves the transplantability of those plants—a great benefit for growers who grow trees and shrubs for retail sale.
Air-pruning also helps plants that are going to stay in their container long term. Being air-pruned will eliminate root circling, which will allow you to keep the plant in the aeration container longer. The plant will eventually get to a certain point and need to be transplanted to a larger aeration container, but the length of time it can stay in the aeration container as opposed to a container that promotes root circling is greatly increased, leaving more time to enjoy your plants before transplanting them.