From reservoir to roots.

01 / Read the whole circuit

Nutrient film technique (NFT) recirculates a shallow stream of nutrient solution through channels containing plant roots. A pump raises solution from a reservoir; the channel slope and return plumbing carry it back. In this model, two channels run in parallel. They share a reservoir but each needs a functioning inlet and outlet.

Start in assembled view, then open the cutaway. The cover supports the plants and excludes light. Beneath it, the roots reach the wetted floor. This is a water-culture system with a small amount of seedling support, not a channel packed with growing medium. The illustrated root mat, water depth and channel slope explain the arrangement; they are not construction dimensions.

Think of the inlet and outlet as two observation points. Seeing flow return from one channel says nothing about its neighbor. A useful inspection walks the circuit in the same order every time: reservoir, pump, both inlets, root zones and both returns.

Reading: Hydroponics (HLA-6442) ↗

02 / Support the plant, leave a path for roots

A basket has two jobs here: hold the seedling at the opening and let roots emerge. In exploded view the basket, support material and root zone separate from the channel so you can inspect that relationship. The assembly lifts only to teach the structure; it is not a procedure for handling established plants.

Media selection depends on the irrigation method, physical stability and water retention. Expanded clay drains readily; mineral wool holds moisture in a formed plug; coir properties vary with processing; loose perlite is light and can escape into plumbing. A material that works in a contained drip bag may be awkward in an open basket above a drain.

For this arrangement, ask whether the starter remains moist until its roots reach the film, whether the basket contains particles, and whether you can remove the plant without dismantling the channel. Follow the medium supplier’s preparation instructions. The model uses enlarged pebbles to make support visible, not to specify a particle grade.

Reading: Soilless Growing Mediums ↗

03 / Measure the solution you actually have

Use source-water analysis to understand what enters the system. pH describes acidity at measurement; alkalinity concerns resistance to acidification. Electrical conductivity (EC) responds to dissolved ions and indicates total salt concentration, not a complete nutrient recipe. Similar EC readings can conceal different nutrient proportions.

Keep a record with the date, source water, solution level, pH, EC, temperature and any additions. Use consistent units and calibrated instruments. Measure again after a change has mixed through the system. Repeated top-ups can alter composition, so a steady water level is not evidence of balanced nutrition.

The nutrient-mixing, meter-scales and crop-stage chapters provide worked quantities with explicit assumptions. Select a program for the crop, fertilizer formulation and analyzed water, then record the stage, method and units before applying it.

Reading: Electrical Conductivity and pH Guide for Hydroponics ↗

04 / Commission the empty system

Use the model as a layout study. An actual installation needs independently chosen dimensions, a structurally adequate frame, suitable contact materials and electrical equipment installed for its environment. Leave room to open the reservoir and remove a channel cover after the canopy has grown.

Oregon State’s NFT guidance specifies a minimum 2% slope for horizontal channels. As a dimensional example, a 2 m run at 2% drops 0.04 m, or 4 cm. Verify the installed fall under load and observe ponding around mature roots. This is a source starting criterion, not proof that any channel length, flow or crop will work.

A useful acceptance record states what you tested and what happened. “Pump runs” is weaker evidence than “both inlets supply water, both channels drain, no joint leaks, and stopped-pump drainage remains contained.” The visible model provides no pump sizing or load-bearing certification.

1. Sketch the actual route and identify every low point, isolation point and accessible drain.
2. Support and connect the empty vessels, supply branches and return, following component instructions.
3. Run a water-only leak and distribution check. Observe both channel inlets and outlets.
4. Stop the pump and observe all drainage and reservoir levels. Resolve overflow or trapped-water problems before planting.
5. Restart, verify delivery and write down the result. Plan how an operator will recognize a pump or power failure.

Reading: Hydro hints: Nutrient film technique ↗

05 / Plant, observe and maintain

A transplant should have roots ready to extend beyond its starter support. In this scene, trace that route through the basket and into the channel. Leafy greens and herbs are common learning crops, but light and temperature still need to suit the crop. Indoor growing requires an appropriate light plan; water delivery alone cannot supply light.

Build the operating record around changes you can observe: reservoir level, inlet delivery, free drainage, new growth and the condition around each basket. Inspect roots and plumbing without crushing or tearing the roots. Keep the same observation order after planting, cleaning or replacing a pump.

Between crops, remove debris and clean accessible surfaces before applying a suitable sanitation procedure. Follow the product label and equipment guidance, including rinsing where required. Schedule work so the next crop starts in a cleaned circuit; a recirculating loop can also move problems between plants.

1. Before a change: record water measurements and which plants or channels are affected.
2. During service: isolate the component safely and keep the intended flow interruption visible to the operator.
3. After service: verify the entire circuit again, including the branch that was not worked on.

Reading: Small-scale hydroponics ↗

06 / Trace a symptom to evidence

The following table is an observation guide, not a diagnosis or treatment prescription. Resolve delivery and measurement uncertainties before changing several inputs at once. Keep dated notes so the next inspection can test whether the intervention helped.

07 / Price the operation as well as the parts

Use the parts list below as a scoping worksheet. It describes the illustrated model, not a complete bill of materials for a validated build. Add supports, compatible fittings, covers, instruments, installation and contingencies for your location.

Separate one-time purchases from recurring costs: seeds, fertilizer, water, electricity, cleaning materials, replacement components and labor. Record lighting and environmental-control costs separately so they do not disappear into a pump estimate. Compare a full crop cycle, including cleaning and unsuccessful plants, before claiming a cost per harvest.

Commercial placements and affiliate links are labelled separately from the lesson. Selection criteria remain readable without following a shopping link.