NFT Return Maintenance and Problem Solving:

NFT (Nutrient Film Technique) is an excellent system, but is prone to several issues if not well maintained.  One such issue has to do with returns, the open sections of pipe at the rear of each NFT level. The end of each rail is inserted into the open return, and gravity pulls water through the rail into the return trough.  From there, water will flow into a 1 inch diameter drain in the middle of each return trough, and from there down a pipe into the reservoir. Many plants growing in NFT will produce a large amount of root mass, which will find it’s way through the rail and into the return trough. Root mass, while a sign of healthy plants, is also capable of causing clogs and consequent flooding if not promptly addressed. Roots of some faster growing plant varieties (e.g., mints, mustards) can potentially grow all the way through the return drain and emerge into the reservoir in just a few days.

Prevention of Clogs Due to Root Mass:

Routine maintenance is key.  At minimum, all rails should be inspected once per week. Any roots protruding from the ends of rails should be trimmed. Particular caution should be taken in removing roots that have already begun to grow into a drain, as if any roots remain in the drain pipe, the potential for clogs is much higher in the future, as roots may dislodge and clog the system.