Raft (Floating Tray) Hydroponic System

Introduction

A raft system-also called a floating tray or deep water culture (DWC) raft-is one of the simplest hydroponic methods. Plants are supported in net pots or small cups embedded in a buoyant raft (often polystyrene or polypropylene), which floats on a nutrient-rich reservoir. Their roots hang directly into the solution, receiving continuous access to water, nutrients, and dissolved oxygen. Because the large volume of water stabilizes temperature and nutrient levels, raft systems excel at growing fast-maturing, shallow-rooted crops like lettuce and herbs :contentReference[oaicite:0]{index=0}.

Building One Yourself (DIY)

1. Gather Materials:
   • Sturdy reservoir (food-grade tote, plastic bin, or pond liner)
   • Buoyant raft material (foam board or high-density polypropylene)
   • Net pots or small plant cups
   • Hydroponic nutrient solution
   • Air pump + air stone (to oxygenate the water)
   • Tubing and fittings for your air pump


2. Construct the Raft:
   • Cut raft material to fit snugly inside your reservoir.
   • Drill or cut holes in the raft to hold net pots-spacing plants 6-8″ apart.
3. Assemble System:
   • Fill the reservoir with nutrient solution, leaving 1-2″ of headspace.
   • Place the raft on the solution surface so net pots float securely.
   • Install the air stone in the reservoir and connect it to the air pump.
4. Plant & Maintain:
   • Insert seedlings or rooted cuttings into net pots with inert media (clay pebbles, rockwool, etc.).
   • Keep the reservoir topped off-replace the entire solution every 7-10 days.
   • Run the air pump continuously to ensure high dissolved-oxygen levels.

What a Professional Kit or System Might Look Like

• Pre-fabricated Floating Rafts: Injection-molded polypropylene rafts with integrated net-cup holes and clips.
• Modular Reservoirs: Stackable or connectable troughs made from UV-stable plastic or stainless steel.
• High-capacity Air Delivery: Multi-outlet air pumps or blower systems feeding air stones evenly throughout large tanks.
• Automated Monitoring: Digital probes for pH, EC, and temperature paired with dosing pumps for on-demand nutrient/top-off adjustments.
• Integrated Lighting & Climate Control: LED grow lights mounted above rafts and sensors to regulate greenhouse temperature/humidity.

Cultivar Suitability

Sources

• First Timer Hydroponics: Raft System (Instructables) :contentReference[oaicite:1]{index=1}
• Deep Water Culture - Wikipedia :contentReference[oaicite:2]{index=2}
• The Main Methods of Hydroponics - BTL Liners :contentReference[oaicite:3]{index=3}