Tomato Root Growth Plugging Hydroponic Drain

by Russ Draper
(Midlothian virginia)

Currently my hydroponic tomatoes are doing fine. Yet, the growth of the root system from the tomatoes have extended down into the trough. The plant closest to the drain has roots extending to the drain. and is slowing drainage. Can I trim these roots (tap roots). I am afraid that the root growth will now be susceptible to root rot. Can you offer any remedies? My homemade hydroponic garden uses a 6 inch tube with a timed pumped...1 minute on 5 minutes off.

Answer: Russ- There are a few things you can do to remedy your situation....or you may choose to do nothing at all! I run several hydroponic systems in which tomatoes and peppers are grown in standing (re-circulating) water. The tomatoes and peppers do not mind being grown in standing water, as long as you include an air bubbler in the nutrient reservoir (to keep the water oxygenated), and also make an effort to keep the nutrient solution temperature at 68-72 degrees.

In your system, your plants are not being grown in standing water. The amount of water that accumulates in one minute of spraying is not significant enough, nor is the duration of their submerged condition long enough, to really be a problem for the tomatoes. If you are still concerned, you can add an air bubbler to your nutrient reservoir. I recommend disturbing the roots of your plants only as a last resort.

In a similar system, I have had the same problem before. I simply cut all of the roots within 1 inch of the drain. I did not have any negative effects from the trimming, although that particular plant did finish a little smaller than all of my other plants. Also, the end plant in my hydroponic system was a full 6 inches from the drain....which still left the plant with approximately 6 inches of thick roots. If your end plant is very close to the drain in your system, trimming might not be a good option (you may have to remove too many roots).

While it may not be possible to do during this particular grow cycle, there are a couple of things you can consider for the next grow cycle. You can extend the system 18-24 inches to move the drain further from your end plant. This may or may not be possible, depending on your hydroponic system design. You can try to manufacture a larger drain in the system....one that will not be affected significantly by the infiltration of heavy root growth. Lastly, you can skip filling the last spot with a plant (which can be disappointing if your system is only a 6 plant system to begin with).

As long as the excess water in your system is not flooding your system, and as long as all of the water drains quickly enough to give the roots of your tomato plants a few moments without any standing water, I would not be too concerned. Personally, I would do nothing. However, I would continue to keep an eye on the situation (to prevent any flooding), and I would still consider extending the drain away from the end plant or manufacturing a larger drain hole for the next grow cycle. I hope this helps Russ, and Happy Growing!