Van der Knaap has researched compact cultivation of kalanchoe in collaboration with the growers of Blos5. Blos5 is a cooperative of kalanchoe growers who work together in the areas of purchase, sales, marketing and cultivation. The research focused on compact cultivation without the use of Tilt. In practice, this chemical growth regulator is most often used to keep the leaves of the kalanchoe compact. In this trial the researchers investigated other strategies, such as the possibilities of substrate and adapted fertilisation, to keep the plant compact.
The trial was set up in collaboration with various parties from the horticultural sector. A total of six different strategies and a reference treatment were tested in Van der Knaap’s innovation centre ‘de Kas’. The treatment with substrate specially developed by Van der Knaap for compact growing, was also tested in practice by the growers of Blos5.
The treatments investigated during this trial are:
- Substrate: a newly developed substrate using alternatives for peat and an adjusted start fertilisation.
- Fertilisation 1: two different treatments with an adapted start fertilisation on the current substrate.
- Fertilisation 2: an adapted nutrition schedule aimed at compact cultivation.
- Biostimulates: an addition of various products to the nutrition water aimed at compact cultivation.
- LED lighting: a strategy based on regular substrate and LED lighting.
- Reference treatment: a strategy based on regular substrate in combination with the use of Tilt.
Two different kalanchoe varieties were selected for the test; Bromo and Leonardo. These are coarse-leaved varieties in which the effect of the various strategies is clearly visible. In addition, CCC and Alar were used for the various treatments. These growth regulators, which are still allowed for use in the coming years, have been used to counteract the stretch of the flower stem.
In this study it was important to keep the leaves of the kalanchoe sufficiently compact. This increases the ornamental value of the plant and simplifies the process of packing the end product. All treatments in this study gave a positive result compared to the reference (treatment with regular growth regulator).
The treatment with Van der Knaap's modified substrate gave the best results. The kalanchoe developed the desired compact leaf without the use of Tilt as a growth regulator. This substrate also enabled compact growth at the locations of the members of the Blos5 group. An additional advantage is that this is a peat-reduced mixture, which is increasingly in demand in practice.