Dissected white ash seeds were placed on an agar-solidified MS medium with 10 μM TDZ and 1 μM 2,4-D (shoot initiation medium). After 4 weeks, explants were transferred to shoot elongation medium (3 μM TDZ, 1 μM BA, and 1 μM IBA) solidified with 0.7% Sigma agar, 0.525% agar + 0.05% gelrite, 0.35% agar + 0.1% gelrite, 0.175% agar + 0.15% gelrite, 0.2% gelrite, or no gelling agent (liquid medium). After 12 weeks in vitro, shoot growth and number were suppressed in cultures containing 0.2% gelrite (9.3 mm and 0.7 shoots) and in cultures containing no gelling agent (6.9 mm and 0.7 shoots). There were no differences in shoot growth and number in cultures containing 0.7% Sigma agar (2.2 mm and 16.5 shoots), 0.525% agar + 0.05% gelrite (2.6 mm and 18.7 shoots), 0.35% agar + 0.1% gelrite (1.6 mm and 17.4 shoots), and 0.175% agar + 0.15% gelrite (2.0 mm and 20.4 shoots). The most vitrification occurred in cultures on medium with the lowest amount of agar, gelrite only, and liquid medium.