The 2011 ASHS Annual Conference

Many vegetable and ornamental bedding plant crops are grown in plug trays and cell packs under greenhouse conditions prior to transplanting into the field or landscape. The development of a large, healthy root system is important for young seedlings to help withstand the shock of transplanting. Seaweed extracts are known to improve root development of horticultural plants as well as to help alleviate some symptoms typically associated with abiotic stresses, such as drought and soil salinity. Greenhouse experiments at the Dr. James S. Craigie Research Center in Cornwallis, Nova Scotia, were designed to test the effects of Acadian^® seaweed extracts (a derivative from Ascophyllum nodosum) on root development in lettuce, melon, tomato, and pepper. Seaweed extract treatments in combination with 10N-52P-10K fertilizer were applied as a drench and compared to plants that only received 10N-52P-10K. The roots and leaves of plants from each treatment were examined with WinRhizo root and WinFolia leaf image analysis systems. Time lapse videos were also used to record results. Replicated trials showed significant improvements in root length, surface area, volume, and leaf area when seaweed extract was applied in combination with fertilizer. Further studies examined the effects of seaweed extract on salinity and drought stress in pepper, lettuce, and tomato. Results showed that seaweed extract extended the time before plants began to succumb to water stress compared to fertilizer treated controls. Seaweed extract was also shown to reduce the negative effects of high soil salinity during early plant establishment. These results suggest that seaweed extract applications improve early root and shoot development and may provide some protection against water and salinity stress.