The 2012 ASHS Annual Conference

Tomatoes are the leading greenhouse vegetable grown in North America and the world. Almost all greenhouse tomatoes are produced hydroponically, using computerized production systems and grown in medias such as rock-wool or coconut fiber. In the United States and Canada, growers normally transplant new plants into their greenhouses in December and the first ripe tomatoes are produced in late March. A greenhouse experiment at the Dr. James S. Craigie Research Center in Cornwallis, Nova Scotia, was designed to test the effects of Stimplex^® (a proprietary extract from the brown seaweed Ascophyllum nodosum) on earliness and yield of hydroponically grown greenhouse tomatoes. Stimplex^® treatments in combination with a standard hydroponic fertilizer were applied to the root systems of tomato plants (Lycopersicon esculentum Mill. var. Trust) through the irrigation system. The growth, flowering and fruit production of the Stimplex^®-treated plants was compared to grower fertilizer only treated plants. Fruit set of Stimplex^®-treated plants was shown to increase by 78% during the first 5 weeks after transplanting. Stimplex^®-treated plants exhibited earlier fruit ripening with a 51% increase in the fresh fruit harvested 8 weeks into production. A 19% increase in yield and a 5% increase in fruit weight were achieved 15 weeks into production. These results suggest that Stimplex^® applications improve the earliness of fruit set and ripening that result in increased yields during the early stages of greenhouse tomato production.