Maximum Yield USA July 2018 | Page 68

“SOLUTION CULTURE SYSTEMS are often seen as the purest form of hydroponics as plant roots are suspended in nutrient- rich water and only a minimal amount of substrate is used to support the plant.” Those early solution culture trials eventually evolved into a wide range of crop production systems used for organic and non-organic hobby and commercial grows. Along with nutrient film technique (NFT), solution culture incorporates many innovative variations of float, raft, raceway, pond, and deep flow technique (DFT) systems. Solution culture is also incorporated into aquaponics, where fish production and hydroponic crops are combined. Commercially, float systems are used to produce vegetable crops such as lettuce, herbs, and other greens. They are also used to raise field transplants. These systems allow growers to evenly water the young seedlings while feeding them a well-balanced nutrient solution that can be adjusted in composition and strength during the critical stages of development before seedlings are transplanted out in the field. Under greenhouse production, large-scale float systems maximize the growing area as the need for pathways is reduced and automation can be adopted where required. On a smaller scale, mini raft systems can be set up with as little as a plastic container, some polystyrene sheet, and a well-balanced nutrient solution, making these systems ideal learning tools for younger students and those with restricted space. Top: NFT systems are ideal for leafy greens. Center: Many small vegetable crops, including scallions, are suited to float systems. Bottom: Mini float systems can be used to grow baby salad leaves on a compact scale. 68 Maximum Yield