This is the big one. Two ebb and flow trays of 2 x 1 metre sit on its two tiers. It reaches 136cm tall and takes up 209 x 96.5cm of floor. We build the frame from 25 x 25 x 1.5mm aluminium with steel-reinforced corners, rated to 40kg per square metre. Bolt on more tiers when you want to grow higher.
A 150-litre tank slides in below the bottom tier. The pump floods both wide trays with nutrient water, then it all drains back once the pump cuts out. That rhythm feeds a big crop of leafy greens or herbs evenly. Ask for wheels if you want it mobile. Trays bought separately.