3.7 Housing
Hyacinths can be brought into the greenhouse from the rooting room or the standing ground as soon as the required cold period (number of weeks at 9ºC) has been achieved. Never house them too early. This leads to a much greater risk of quality problems like “top flowering” and top rot, as well as to an extension of the greenhouse period. Top rot is a condition in which the florets that were the last to differentiate, especially those on the largest flower clusters, dry out. The damaged areas then form entries for Penicillium mould which causes these florets to rot.

Temperatures above 9°C and under 5°C do not count as full cold for hyacinths, so that the cold period will have to be extended if the temperature remains under 5°C or over 9°C for longer than 2 weeks. Unfortunately, it is difficult to indicate by how long the cold period should be extended. The additional time can range from a few days to 3-4 weeks.

Water should be provided and the r.h. of the greenhouse air should be increased to 80% immediately after housing.