2017 ASHS Annual Conference

Future success of controlled environment agriculture will demand low-cost, multiple-cropping production strategies nearer to major population centers and allowing efficient use of fertilizers and water. The main system of hydroponics for production of leafy greens is the Nutrient Film Technique (NFT). Rockwool is commonly used as a seed starting substrate, but is priced higher than other potential seed starting substrates. This study evaluated three different substrates including rockwool cubes, oasis cubes, and foam cubes for seed starting and plant growth in an NFT system. Two cultivars of lettuce including ‘Mirlo’ , and ‘Rex’, both butterhead types, and Swiss chard ‘Rainbow Chard’ were evaluated for their fresh weight of leaves and dry weight of roots in different mediums. The mean height, width, fresh weight, dry weight, and root dry weight of plants grown in rockwool cubes and oasis cubes were significantly higher than plants rooted in foam cubes for all species. Although rockwool and oasis cubes had similar results, the cost of rockwool cubes is higher than the cost of oasis cubes. Seedling survival rate was not significantly different among three mediums, but germination took two weeks longer in foam cubes.