This system is a nutrient film layout built for a tomato house, with food grade PVC channels carried on galvanized steel support pipes and the feed run automatically rather than by hand. A thin film of solution moves along each channel past the roots, so the crop is fed and watered in the same pass and the solution that leaves the channels can be collected and returned to the tank. Channels are white, which keeps the root zone cool and the working area bright, and the layout is set to the house and the row spacing.
Tomato is usually grown in soil or in a substrate, and both carry a cost that a nutrient film system removes: the soil has to be sterilised or replaced, and a substrate bag is used once and thrown away. A film system puts the roots in a flowing solution instead, so the water and the fertiliser can be recovered rather than lost, and the root zone can be changed between crops without lifting soil.
The premise of a nutrient film layout is that the roots do not need to be submerged. A shallow stream of solution running along the channel floor gives them water, oxygen and nutrients at the same time, and because the film is thin the solution stays aerated as it moves. That combination is difficult to reproduce in a deep tank and it is the reason the system gives such even growth along a row.
It also fits the way a tomato house is already built. Rows run the length of the bay, the crop is trained upward, and the whole house is worked from a central aisle, so a channel laid along each row line replaces a bed at no cost to the layout. Hydroponic growing under cover is set out more widely on the hydroponic system range page on this site.
Channels are food grade PVC in white, held level to a small fall along the run so the film moves at a steady speed rather than pooling at the low end. Support is a galvanized steel pipe frame, which carries the channels at a working height and lets the layout be set to the row spacing of the house instead of the other way round.
The fall, the channel length and the number of rows are set together, because a channel that is too long for the fall will not keep a film across its whole length, and the plants at the far end will starve first. That is the single calculation worth getting right at the design stage, since it decides how the house is divided into blocks. A house that runs the same layout under a film cover is described in the single span hydroponic house for tomato and cucumber.
The feed is automated, so the system runs to a set point rather than to a manual valve. In practice that means the pump cycles through the day on a timer or a sensor, the tanks are topped up and dosed on the same schedule, and the return line carries what is not taken up back to the tank instead of running to waste.
Because every plant on a channel shares the same solution, the system is only as even as its flow. Filters and the return are the parts that keep it even, and a blocked filter or a pump running slow shows up along the row rather than at one point, which is why they are checked on a cycle rather than when the crop looks wrong. A system built on the same principle in a turnkey house is described in the turnkey hydroponic tomato house.
The table below is the standard build. Channel length, row spacing, support height and the control package are set to the house and to the crop.
| System type | Nutrient film, channels with a shallow flowing solution |
| Channel material | Food grade PVC |
| Channel colour | White |
| Support frame | Galvanized steel pipes |
| Feeding | Automated pump cycle with dosing and tank top up |
| Drainage | Return line to the tank for recirculation |
| Crops | Tomato, leafy vegetables, herbs, flowers and microgreens |
| Use | Inside a greenhouse or a controlled growing room |
| Customisation | Channel length, row spacing and support height set to the house |
The system arrives as channel lengths, fittings and support pipe, and is assembled in the house rather than fabricated on site. The support frame is set out and levelled first, because the fall along each run is what makes the film work, then the channels are laid in and the feed and return are connected to the tank and the pump.
Maintenance is the water and the flow. Filters are cleaned and the tanks are checked on the same cycle as the crop, the return line is flushed when the block is turned over, and channels are washed between crops so that root material does not carry over from one planting to the next. The pump and the dosing unit are the working parts, so they are serviced on a schedule rather than on a failure.
Systems of this type are used for tomato production in a greenhouse, for leafy vegetables and herbs, and for microgreens and flowers where a clean root zone matters. They suit growers converting a soil house to soilless production, operations that are short of clean water and want to recirculate, and greenhouses that expect to add dosing, monitoring or a full control layer to the same layout later.
Research and extension material on protected crop production, including work on soilless growing and controlled environment agriculture, is published by the Controlled Environment Agriculture Center, University of Arizona. Production and market reporting for growers working under cover is published by FloralDaily. The specification that matters is the one that still suits the crop ten years from now.
Because the roots need oxygen as well as water. A shallow stream running along the channel floor keeps the solution aerated as it moves, and it gives the roots water and nutrients in the same pass without drowning them.
The fall along the run. A channel that is too long for its fall will not hold a film over the whole length, and the plants at the far end are the first to suffer, so channel length and fall are set together at the design stage.
The PVC channels and the galvanized support frame are both built for long service under normal growing conditions. Channels are handled most, so they are checked and replaced individually rather than as a set.
We provide a 10 year structural warranty and a 5 year anti-corrosion warranty on the galvanized support. Details are set out in the contract for each project.
Send your house dimensions, the crop you plan to run and the way you want the rows divided. We reply with a layout drawing and a full quotation.
