Overwatering: A Lesson for New Hydroponic Growers
I recently set up a new flood and drain hydro system to start growing some things right outside my dorm room. Initially, I had a full-blown bell siphon which took a few weeks to perfect, but worked very reliably afterwards. I had about two square feet of growing space, and even set up a supplementary LED grow light to provide additional light.
Originally, I had planted five pea plants in my system, and they were doing fine for weeks. However, as I upped the nutrient concentrations in preparation for extreme vegetative growth, I noticed that I was soon having a bacterial growth problem. Clobs and clobs of white slime were slowly taking over my plants. Very soon, my plant leaves started to wilt, and I thought I would lose the whole crop.
To cope with the overgrowth, I added a quart of hydrogen peroxide to the system, and very soon, not only were the bacteria dying, but the plants were doing extraordinarily well. At this point, I realized that what the plants needed most was not water, but oxygen to the roots. Turns out that overwatering is as unhealthy for plants as underwatering.
The problem with the bell siphon that I had built was that it only started draining the water after it had already reached the top of the grow media, which meant that all of my hydroton got very wet, which made it the perfect breeding ground for bacteria. To fix this, I converted my flood and drain system to a simple drip system. Although this didn’t have as much of the “cool factor” as the bell siphon, I noticed that this system got rid of my bacteria problems, and also resulted in much healthier looking plants.
So what did I learn from this? Plants need oxygen too, and it’s really important that they get enough oxygen to their roots in order for them to thrive. Otherwise, your system will turn into a nice breeding ground for plant-killing bacteria.
Here are the lessons I learned:
Rockwool should NEVER EVER be fully submerged in a full production system. Rockwool is great at retaining water, which means that if it’s continuously soaked in a full system, it will never let enough oxygen get to the roots. Ensuring that your roots are well oxygenated is the best way to prevent root rot.
The water level should never come above the growth media. Wet growth media is like a free feast for bacteria, and you can be sure that they will not only starve your plant of nutrients but also cause massive root death.
Plant roots need lots and lots of Oxygen, not just water
Using Hydrogen Peroxide on bacterial overgrowth is the most rewarding thing ever. For those of you who have never staged a mass bacterial genocide with Hydrogen Peroxide: you are truly missing out. Imagine seeing all the evil things that are eating your plants bubble away in one glorious dump of peroxide. The extra oxygen delivered to the plant roots is just icing on the cake.