A Hydroponic Mold Problem

by Bob
(Fish and Jacks Canada)

I set up a hydro system as in the article "My Most Successful Homemade Hydroponics System". Into day 7 and it appears that mold is growing on the roots, or am I mistaking this with algae? The res is covered, not allowing any light into the nutrients solution as well as the PVC piping.

Would the rate of flow of water through the system allow for mold to grow on the roots? I could send u a picture of the mold or algae in question as this is my first time and not certain about the growth in question. Thanks, Bob.

Answer: Bob- Mold will not usually attack the roots of your plants whenever they are submerged under water, as all of the mold varieties I am familiar with require full-air in order to survive. Depending on the color of the film on your roots, I suspect one of two things. If the layer is some shade of brown, it is likely just an organic film made up of nutrients and beneficial micro-organisms. If the film is green, however, and very small thread-like strands are beginning to hang off the film, than the problem is definitely algae.

If you gently rub on one of the affected roots, the layer should rub away and show a white, healthy root underneath (or possibly stained slightly off-white is OK too). If you rub on the affected spot and it is black, or if it simply disintegrates in your hand, than the roots could be dying back due to lack of oxygen in the standing water. Hopefully you have included air bubblers in your nutrient reservoir and this is not the case. If it IS the case, you have a more serious problem. All of the dead root tissue in the system will attract and grow a large population of some very nasty micro-organisms that like to colonize and destroy roots- like pythium or fusarium.

So, give the roots another check. Make sure you have air bubblers aerating the nutrient solution. And double check the temperature of your nutrient solution....it should be between 67 and 72 degrees ideally. Any warmer than that, and the water cannot hold the dissolved oxygen and the solution will begin to favor the bad micro-organisms. I sure hope this helps you out Bob.