Effect of Post-planting Temperatures on Root Elongation of Hydroponically Forced Tulip Bulbs

The effect of post-planting temperatures on root elongation of precooled bulbs from 13 tulip cultivars that were grown hydroponically was studied. Root dry weights and optimal temperatures for root elongation differed greatly among cultivars. A similar response was obtained in both water and pumice cultures. Our results indicate that success for early forcing depends on using suitable cultivars, according to the soil temperature available at the time of planting.