NFT – Nutrient Film Technique – runs a shallow, continuously moving film of nutrient solution along the base of a sloped channel. Roots sit in the film; the top of the root mass stays in humid air. There is no growing medium at all beyond the propagation cube the plant starts in.
Why the film has to be thin
This is the whole design. If the solution is deep, the roots are submerged and starved of oxygen. A genuine film – a few millimetres – means the lower roots take up water and nutrient while the mass above them sits in air. Get the slope and flow right and you have near-perfect uptake with almost no equipment.
What it does well
Very fast growth from constant nutrient availability and high root oxygen.
No medium to buy or dispose of. Just channels, a pump and a tank.
Easy root inspection – lift the lid and look. Problems are visible days before they would be in a pot.
Cheap to run at scale once built.
What it does badly
NFT has the least buffer of any system except aeroponics. A pump failure leaves bare roots drying in hours. Root disease spreads through the whole channel because every plant shares the same film, so reservoir temperature is critical – keep it under 22°C and run beneficial bacteria to suppress pythium. It also suits smaller, evenly sized plants better than a few large ones, because a big root mass will dam the channel and flood the plants behind it.
Setting it up
Slope: roughly 1:30 to 1:40. Too flat and it pools; too steep and the film outruns the roots.
Flow: about 1 litre per minute per channel is the usual starting point.
Start plants in a cube – see propagation media – and set them in the channel once rooted.
Filter the return. Root debris in the pump is what stops the film.
We are a hydroponics shop in Croydon and we have run NFT for years. We will tell you honestly whether your space and plant count suit it. Discreet UK and European delivery, and excellent customer reviews on Trustpilot.
