The basic schedules for managing rooting rooms of spring bulbs are well known, thanks for the extensive work done by Gus de Hertogh from the inception of the Dutch sponsored research program. Basically, a temperature sequence of 9C (48F) followed by 5C (41F) and eventually to 1C (33F) is used. The changes in temperature are theoretically according to growth stage of the crop. So, the switch from 9C to 4C occurs when the roots grow out the holes in the pot and the switch from 5C to 1C is then the shoots are about 1” long. The reduced temperature prevents the shoots from growing up into the crates and pots stacked on top.
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