I’ve been contemplating this statement quite a bit lately.
To head off any problems I wanted to make a simple list of thoughts to consider for healthy roots. If anyone disagrees with anything or feels I missed something important please chime in.
- Roots need O2 (air exchange)
- Roots hate light
- Root zone temp matters
- Too much airflow will cause air pruning of roots
- HPA mist will escape if you have big leaks
- Contaminants in the root zone can lead to rot or other problems (pests)
Since my root zone is a sealed chamber with a PVC drain back to the reservoir I believe the only issue I will have to focus on will be air exchange. When I originally designed this I had assumed that the highly oxygenated water going through the nozzles would provide enough O2, but re-reading Atomizers threads got me thinking this probably isn’t enough.
This next iteration of the system includes a constant waterfall travelling down 3 sides of the chamber, across the bottom, and out the drain. This is the same water from the reservoir and is meant as a way to cool the root zone and provide a secondary heavy feeding source when roots reach the bottom. While this will provide a source of dissolved oxygen once the plants reach that point it still doesn’t help circulate the air in the chamber itself.
I kept reading the different ways people handled the air exchange when I came across a discussion about maintaining positive pressure inside of the root chamber. I already have a good outlet for excess air via the drain so I started thinking about ways to introduce fresh, clean air into the chamber without creating too much airflow to cause pruning.
I already have a good air pump running to the reservoir and it just happens to have an adjustable manifold on it with extra ports. As a test I went ahead and picked up a few items to play with.
Since I will want to be sure the air I’m introducing is clean I picked up some cheap little in-line HEPA filters.
Then another manifold so I can restrict the airflow even further after the filter.
Right now I’m not sure how I’ll introduce the air into the chamber, but I’m thinking of a diffuser – perhaps turned upside-down so there’s not a constant flow hitting the lower roots.
As I was writing this up I noticed @HappyHemper and @MicroDoser discussing this very thing over on Larry’s thread.
So now I think I’ll have another fun test to play with during this next run. I plan on running the same two clones again so I can compare vs this last harvest, but maybe I’ll add a second BK in the third bed and use that to play with air. Or maybe I’ll just go all-in, who knows…