Building this 30 plant site NFT system was challenging, and a lot of fun. Finding all the necessary components was the challenging part; putting it together and having it work was the fun.
Basically, it's three channels, or gulleys, fed by a submersible pump in a reservoir. Water is pumped up through a manifold which supplies the jet pipes in each gulley. Water flowing along the bottom of the gulleys and splashing on the net pots keeps the plant roots moist, nourished, and oxygenated.
Each gulley is a 4"x4"x6ft vinyl fence post jacket with caps for same glued and sealed onto each end. Holes are drilled for the plant sites, the drain, a drain access port, and a pass-through for the spray lines.
The reservoir itself supports the gulleys on one end, and a saw-horse type structure, the other. Holes are cut in the reservoir's lid for the gulley drains, the supply line from the pump, and an access port to check the water level and refill.
Other parts and fittings include:
- Female hose bib to 1/2" compression elbows to attach 1/2" CPVC capped-end spray bars to the manifold
- Plastic C clip brackets, bolts & nuts to attach spray bars to upper inside of gulleys
- 3/4" PVC Ts and elbows to fabricate manifold (slip x slip x thread)
- 3/4"NPT x male hose thread nipples to attach compression elbows to manifold
- 1-1/4" x 9" plastic lavatory drain pipes for gulley drains
- Various grommets for drain pipe and spray bar seals
- 750 gph magnetic drive submersible pump
- 3" net pots and hydroton expanded clay media
It would have been better to construct the unit using 5"x5" fence post jackets, but none were locally available. Using such would have allowed standard 4" diameter test plug caps to cover the drains, and would also have required the manifold to be constructed using 1" PVC fittings with 3/4" threaded outlets. I would also, in retrospect, have done better to pass the ends of the spray lines all the way through the other end cap, and terminate them with threaded caps, which would have allowed for easy cleaning with a long, thin tubing brush.