Shirokuma
Newly Registered
Posts: 3
Joined: Sat Sep 09, 2017 8:12 am

NFT advice

Hello,

I want to start a bioponic system at my farm and want to put this also outside.
At this moment I have no hydroponic, bioponic, aquaponic,... experience but have been studying books.
This winter I want to take the opportunity to start building prototypes and after success to expand it.
But multiple idea's that I have, I can not find in anywhere.
I want to cover a 40x5meter field with NFT tubes that are suspended by a wire.
The pipes will hang in the 5 meter direction and will be also 5 meters long.
The reason for suspending on wire is when it is harvest time I can pull out that NTF tube and don't need to walk between the tubes. Because the whole field can be full of NFT tubes without walking space I am only limited by the planting space.
I was thinking to connect the tubes with couplings that can be easily coupled or uncoupled. A little bit like a gardena coupling.
Why I never see NFT tubes be hanged up on wires but always on a frame/table?
What can be the problems with my way of hanging up the tubes?

Another thing what I often read that is a possible problem is DO levels.
I was thinking to increase DO levels by using mister irrigation nozzles pointing inside the tube instead of just letting it run by hose the tube.
This way there would be big increase of oxygen just before going to the plants (where it is most needed). While using airstones in the sump would already have lost a certain amount of DO before even reaching the NFT tubes.
Is there a reason that I am overlooking that this is not done so often?

Please give feedback and advice,
Thank you

imafan26
Mod
Posts: 13961
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

Most hydrosystems run partially on gravity flow. Usually the tanks are low or underground since temperature is easier to control that way and the nutrient solution is pumped up to the grow beds, tower, or rails. The grow beds drain back to the reservoir by gravity.

Unless your property slopes down hill it takes a lot of force to run water through a long skinny tube. If you raise the tube higher than the anti siphon devices, you risk contaminating your supply and clogging at the filter. Water will seek its own level.

If you raise the tube you will actively have to pump it to overcome gravity. If your lines are too long, there won't be enough water at the end of the line. You have to keep the lines straight, not on a wire but on a wood frame or along a bench or wall. On a wire the tubing will sag, at those points water will slow and collect, you need to keep the water moving preferably at a steady rate in one direction.

People do run over head drip lines. They have tanks that are raised not in the ground and they run their lines slightly downhill so gravity works for them and they keep their lines straight without any parts sagging by using either a pvc delivery system or they attach the tubing to a rigid surface like a beam or a wall. You can actively pump the water through the lines but you have to make sure you do not exceed the pressure rating of the system or it will burst with a pressure regulator. Pumping from the end of the system back up to the reservoir would still be required.
You will have to calculate your water pressure and GPM to determine how many emitters you can support on a line. Most lines cannot exceed a certain distance and the lines cannot exceed the max pressure for the system.
Because the rails are filled with air and the water flows past the roots, there will be air roots in the tube so oxygenation in the tank is really all you need.

On a rail system there is usually only one or two tubes per rail. They are relatively short so they actually don't get in the way of harvesting. The water valve nearest the emitters are turned off and the emitters are pulled out (usually 2 hort tubes. the rails are pulled out and harvested across the aisle, then the rails are put back in place and then the tubes reinserted.

Theses are the rail systems I am used to. We used the oasis cubes to start the seeds. They were started in a tray with the hydro solution. They never grow in dirt. The cubes are inserted in the net pots in the rails and they stay there until they mature.
https://www.youtube.com/watch?v=RDmI_tjj0N8
https://www.youtube.com/watch?v=zHyJKp2bgFA

Shirokuma
Newly Registered
Posts: 3
Joined: Sat Sep 09, 2017 8:12 am

Imafan,

Thank you for your great advice, you probably saved me a lot of money.
It changed my mind so I will also put it on a frame like in your movies.
This winter I will start construction in my greenhouse of a prototype.
If this is successful I will enlarge it to the 40x5m field.

imafan26
Mod
Posts: 13961
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

cGreat. There are organic hydroponic solutions but they don't work very well at least at this point in time.
The commercial synthetic fertilizers dissolve well, have guaranteed analysis and they don't have a lot of rubbish that can clog the emitters or snag the roots and cause them to decay. Healthy roots should be white not brown or black. If anything slows the flow you will lose oxygen and build up fungi and bacteria which will harm the plants. It is why you don't want anything to impede the flow of the solution.

johnpradeep
Full Member
Posts: 19
Joined: Fri Nov 09, 2018 8:22 am
Location: Chennai

Thanks for this informative post.



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