Sunday, 14 June 2015
I have a very small garden, so space is limited.
A reliable NFT system was therefore high on my priority list.
Vertical expansion would also allow me to maximize on summer crops.
Some things fell into place immediately. NFT requires constant flow so an additional dedicated pump was essential. Flow rates of one to two liters per minute so only a small pump required.
One condition I set myself was to use only readily available UK household plumbing parts.
Just to recap. NFT or near film technique requires just that a, “Film” of water. Say 1 to 3mm deep.
This means, ‘round pipes are NOT suitable’
Using round pipes of various diameters is a tried and tested method that works BUT I think it is better called, ‘Shallow DWC’
So the choice of 6 cm square line drain pipes was easy. 5cm holes cut at suitable interval perfect fit for net cups and a one centimeter gap at the bottom.
I use 22mm pipe for water supply. This will connect to a readily available four way manifold. Each of the four outputs are standard 10mm push fit. 10mm push fit ball valves on each allows individual control.
You can seal the open ends with a standard 90* bend glued into place. I found push fit end caps on E bay which with a little bit of silicone work well. Cheaper too.
The next step is the water outlet. Here I used 20mm electrical conduit bulk head fittings. The standard 22 mm bulkhead profile is just too high.
Plastic washer cut from old milk bottle seals it well.
NFT requires super clean water so, in addition to the system filtration, I slip a plastic pan scourer under the water inlet. Ten for a £1. They also act as a spreader and help reduce pooling.
This is Plan H. So far so good.