Granular Gels as Growth Media for Tomato Seedlings

The granulated, insoluble acrylamide-based hydrophilic polymers, Terrasorb HB and Alcosorb AB3C, hydrated initially with all the essential nutrients (15 g gel solids/liter of 1-fold Hoagland solution), were effective media for the production of 3-week seedlings of tomato ( Lycopersicon esculentum Mil.) in plug (modular) trays. Higher concentrations of the nutrient solution used to hydrate gels or incorporation of resin-encapsulated, slow-release fertilizer (Osmocote, 17N–3.9P–10.8K, 1.5 or 3.0 g·liter –1 ) in the hydrated gels decreased seedling growth. Daily application of fertilizer solution (100 mg N/liter) or water resulted in similar seedling growth. Seedlings were healthy, with roots permeating the voids between the hydrated granules of the entire gel mass. The gel mass adhering to the root system could be extracted readily and intact from the plug tray cell.