INFLUENCE OF LATE FERTILIZATION IN THE FIELD ON FORCING AND QUALITY OF POTTED CAMPANULA-CARPATICA

Potted Campanula carpatica 'Dark Blue' are propagated vegetatively, an d grown in the field during summer prior to forcing in the greenhouse. Continuation of fertigation late in the fall had significant negative effects on forcing behaviour and the quality of the finished plants. Plants that were forced after fertigation was terminated in week 45 (m id-November) had significantly higher leaf nitrogen than controls, whe re fertigation was terminated in week 38 (mid-September). The delayed termination of fertigation resulted in reduced shoot number per plant, slightly longer time to flowering, significantly shorter shoots and a 50% reduction in the number of flowers per plant. Plants fertilized l ater than week 38 had a reduction in post-harvest keeping quality. (C) 1997 Elsevier Science B.V.