by Alex Robles
Greetings fellow cultivators, I hope everyone’s day went well. Today I’m going to talk about air pruning pots for a bit. In the “Guide Book for Native Propagation” Julia Walker describes air pruning like this.
“Air pruning happens naturally when roots are exposed to air in the absence of high humidity. The roots are effectively “burned” off, causing the plant to constantly produce new and healthy branching roots. If roots are not exposed to air, they continue to grow around the container in a constricted pattern. Healthy, highly branched root structures allow a plant to more efficiently uptake water and nutrients while increasing growth and overall plant health. A strong root system will make a plant better able to establish itself.”
This is the basic idea behind fabric pots like “Smart Pots”. They help keep the root system from getting pot bound with amazing results. Fabric pots also help hydrate the plant by wicking moisture around the root system. There’s only one criticism I’ve ever had or heard about and that is that they’ll sometimes sag especially when you’re trying to stake the plants limbs down.
The solution that I’ve found for this is to make a transplant pot into an air pruning pot, I call it a Rocketpot. I do this by taking out large pieces of the transplant pot and lining it with felt. Since the transplant pot is just there to act as a frame to keep the fabric rigid and upright, it doesn’t matter how much of the pot is taken away as long as there’s enough open space to let air pruning happen. I used a drill and different size hole saws to do this.
I like to use felt because I will reuse it, but I know people who have used reusable grocery bags or black landscaping fabric as a pot liner. I start by cutting out a circle of felt the size of the bottom of the pot. Then I’ll measure the depth and circumference (length) of the pot and cut the felt 3-4 inches longer so it will overlap in the pot since there’s no gluing or stitching involved. I don’t glue or stitch the fabric because it’s easier for transplanting when the fabric just peels away instead of having to be cut away from the root system and seem to cause less trauma.
For this hack I used:
- 3 gallon pot
- 3 inch and 1-3/4 inch hole saw
- cordless drill
- black felt
These next images show how the roots grow in the open areas. The roots seem to get bound up only at the bottom where there was very little air circulating.
This garden hack can be scaled up to any size, it just depends on what material you use as a frame. Let me know what you think. Leave a comment or a question.
Grow, Learn, Teach