Articles
REDUCTION OF BOLTING IN SELF-BLANCHING CELERY, CELERIAC, ENDIVE AND CHINESE CABBAGE
Under the climatic circumstances prevailing in Belgium (51° North lat.) it was therefore possible to start planting in plastic houses on March 25th 1980 and, under perforated plastic cover, from April 4th onwards.
Harvesting could start at the end of June.
The celeriac C.V. Bronskogel (Huizer) is much more bolt-sensitive than the self-blanching celery Long Doré Amélioré. In 1980 planting-out under perforated plastic cover could therefore not begin until after April 17th and harvesting started early in September.
The available data concerning the endive C.V. Sinco (Pannevis) allowed us to adopt the working hypothesis that an average temperature of 12° C and a minimum of 6° C could be taken to constitute the upper limit of vernalisation.
By applying temperatures not lower than 16° C during a raising period of 35 days it is therefore possible to tidy over a vernalising period of one month.
A raising period of 21 days in the same circumstances allows a vernalising period of 15 days to be overcome.
In the Belgian circumstances of 1980 planting dates under perforated plastic cover were april 4th and 22nd respectively and harvesting took place 2 months later.
For the Chinese cabbage C.V. Hong Kong (Royal Sluis) we assume that temperatures below 11° C and a minimum of 5° C are bolt-inducing.
A vernalising period of about one month under perforated plastic cover could again be tidied over with 72 % of plants that were raised for 21 days at a minimum temperature above 16° C, provided that harvesting took place on May 30st.