Nutrient Film Technique

Introduction

Nutrient Film Technique (NFT) is a hydroponic method where a thin, continuous film of nutrient solution flows over plant roots in shallow channels. Developed in the 1960s by Dr. Allen Cooper in England, NFT has become one of the most widely used systems in commercial hydroponics, particularly for leafy greens and herbs.

NFT is a step up from passive systems like Kratky, offering better scalability and continuous nutrient delivery — ideal for growers ready to move beyond the basics.

How It Works

1. Channels — Slightly tilted PVC pipes or purpose-built channels hold the plants in net pots along the top.
2. Nutrient Flow — A pump pushes nutrient solution from a reservoir to the high end of each channel.
3. The "Film" — The solution flows as a thin film (just 1-3mm deep) along the bottom of the channel, passing over the plant roots.
4. Gravity Return — The channel's slight slope (1-3% grade) lets gravity pull the solution to the lower end, where it drains back into the reservoir.
5. Continuous Cycle — The pump runs continuously, providing a constant stream of nutrients and oxygen to the roots.

Best Crops

NFT excels with lightweight, fast-growing plants:

• Lettuce — All varieties, from butterhead to romaine
• Herbs — Basil, cilantro, parsley, chives
• Leafy Greens — Spinach, arugula, kale, Swiss chard
• Strawberries — Compact varieties do well in vertical NFT setups
• Bok Choy — Grows quickly and loves the continuous nutrient flow

Avoid heavy fruiting plants (tomatoes, cucumbers) — their root mass can block the thin nutrient film and clog channels.

Getting Started

1. Build or buy channels — PVC pipes (3-4" diameter) with holes cut for net pots, or flat-bottom NFT channels.
2. Set the slope — Mount channels at a 1-3% slope (about 1" drop per 3 feet of length).
3. Connect plumbing — Run tubing from a submersible pump in the reservoir to the high end of each channel. Install a drain at the low end back to the reservoir.
4. Mix nutrients — Fill the reservoir with pH-balanced nutrient solution (pH 5.5-6.5).
5. Plant and run — Insert seedlings in net pots, start the pump, and verify flow reaches all channels evenly.

Recommended Supplies

Tips for Success

• Keep the film thin — Too much water in the channel can suffocate roots. You want just a thin film flowing across the bottom.
• Check flow daily — Roots can grow into and block channels. Inspect regularly.
• Have a backup plan for power outages — Without the pump running, roots dry out quickly. A battery-backup pump or alarm system is worth the investment.
• Clean channels between crops — Flush with a mild hydrogen peroxide solution to prevent biofilm buildup.
• Start with a simple 2-4 channel setup — Master the basics before scaling up.

Frequently Asked Questions

What is NFT hydroponics?

Nutrient Film Technique (NFT) is a hydroponic method where a thin, continuous film of nutrient solution flows over plant roots in shallow, slightly tilted channels. A pump pushes solution from a reservoir to the high end of each channel, gravity pulls it along the bottom past the roots, and it drains back into the reservoir for recirculation. Developed in the 1960s by Dr. Allen Cooper in England, NFT has become one of the most widely used systems in commercial hydroponics.

How much does an NFT system cost to build?

A basic home NFT system with 2-4 channels can be built for around $80-150 using PVC pipes, a submersible pump, tubing, net pots, and a reservoir. Using 3 or 4 inch PVC pipe is the most affordable channel option, though purpose-built flat-bottom NFT channels cost more but are easier to maintain. Add a pH and EC meter and nutrients, and a complete setup runs roughly $120-200.

What are the best crops for NFT?

NFT excels with lightweight, fast-growing plants including all varieties of lettuce, herbs like basil, cilantro, parsley, and chives, leafy greens such as spinach, arugula, kale, and Swiss chard, compact strawberry varieties in vertical setups, and bok choy. Avoid heavy fruiting plants like tomatoes and cucumbers because their root mass can block the thin nutrient film and clog the channels.

Is NFT good for beginners?

NFT is a step up from passive systems like Kratky and basic DWC, so it is better suited for growers who have some hydroponic experience and are ready to move beyond the basics. It requires a pump running continuously, regular channel inspection for root blockages, and a backup plan for power outages since roots dry out quickly without flow. Starting with a simple 2-4 channel setup is recommended to master the basics before scaling up.

How often do I need to maintain an NFT system?

NFT systems require daily attention. You should check the flow in each channel daily because roots can grow into and block channels, and verify that the nutrient film remains thin rather than flooding. The reservoir pH and EC should be monitored and adjusted regularly, and channels should be cleaned with a mild hydrogen peroxide solution between crops to prevent biofilm buildup. Having a battery-backup pump or alarm system is also worth the investment in case of power outages.