Nutrient film technique (NFT)

• Plants are grown in channels through which a thin film of nutrient-rich water flows constantly.
• The roots of the plants are suspended in water, and the water flow is designed to be just enough to create a thin film of water around the roots without flooding them.
• The channels are typically made of plastic and are sloped slightly for the nutrient water to flow by gravity.
• The water is pumped into the top of the channels and flows through the roots of the plants before returning to a reservoir.
• The nutrient solution is then recirculated and the water is continuously reoxygentated.
• Not recommended for heavy-fruiting plants, which need a stable support structure and a more consistent water supply.

Advantages

a. Efficient nutrient use:

• Nutrients are supplied directly to roots in a flowing film, reducing wastage.
• Easy to maintain optimum pH and EC.

b. Excellent root aeration

• Continuous flow and thin nutrient layer ensure good oxygen availability to roots.
• Prevents waterlogging and root suffocation.

c. Water saving

• Uses 70–80 percent less water compared to soil cultivation.
• Nutrient solution is recirculated.

d. High productivity and quality

• Promotes rapid growth, uniform development, and higher yields.
• Produces clean, residue-free crops.

e. Flexibility and space efficiency

• Suitable for small areas, rooftops, and vertical farming systems.
• Easy to scale up for commercial farming.

f. Ease of automation

• Compatible with sensors, timers, and automated nutrient delivery systems.

Disadvantages

a. High initial cost

• Requires investment in channels, tanks, pumps, and monitoring devices

b. System dependence

• Relies heavily on continuous electricity for pumping solution.
• Power failure or pump breakdown can cause crop loss within hours.

c. Disease spread risk

• Waterborne pathogens (e.g., Pythium) spread quickly through the circulating solution, affecting all plants.

d. Limited crop suitability

• Works best for leafy vegetables, herbs, and shallow-rooted plants.
• Not suitable for deep-rooted or large fruiting plants without modification.

e. Technical management required

• Regular monitoring of flow rate, pH, EC, and nutrient balance is essential.
• Small mistakes can stress or damage plants.

f. Clogging issues

• Roots may block channels, reducing nutrient flow.
• Algal growth in pipes or troughs can obstruct circulation.