Sustainable cultivation in the greenhouse

Researchers look at three themes: the emissions of CO2, water & nutrients and crop protection. To start with CO2. The four crops have been in the Greenhouse2030 in Bleiswijk since spring 2019. This greenhouse does not use gas for heating: it is a so-called all-electric greenhouse with Full LED lighting. The dehumidification takes place through condensation on a cold surface, whereby latent heat is recovered. This keeps the greenhouse more closed in winter and spring.

The CO2 emissions of the cultivation are minimal due to the use of a Full LED lighting and high insulation of the greenhouse through three screens. The chosen strategy of intensifying cultivation also appears to have positive effects on production. Firstly, more strawberry plants per square meter can be grown by reducing the distance. And by making the gutters hoistable, there is still room for harvesting. As a result, the Greenhouse2030 has 20% more plants than usual. The production increased much more than that 20%. In practice, a harvest of 15 kilograms is achievable, in the project more than 22 kilograms per square meter were achieved. The taste of the strawberries of the cultivated variety was very good.

Gerbera and potanthurium

Production at gerbera also rose sharply. This applied to both the small-flowered gerberas and the large-flowered gerberas. In the autumn and winter months, 2 flowers per week could be harvested more per square meter (on an annual total of 530 small-flowered and 390 large-flowered gerberas), while less heat was required. The production of potanthurium also increased: more flowers and a higher weight. This increase was mainly due to the second part of the cultivation. At the start, the young crop had to get used to the high amount of light, which it was not used to when growing on other farms.

Then the emission of water & nutrients and crop protection. The crops were placed on a gutter, table or 'container', allowing complete recirculation. Something that is still a rarity in soil-grown cultivation such as freesia. In the field of crop protection, various challenges remain. For example, there are still many questions about the prevention and control of mildew in gerbera and strawberry. There is also a lot of attention for creating a good living environment for biological controllers from the start of a cultivation.

Parasitoids pollinate flowers

The researchers discovered something remarkable in the field of biological control agents. This is that parasitoids also pollinate flowers. That way, natural fighters can perhaps help bees in the winter. Bees are not very active during that period, while pollination must take place in the strawberry.

The 'Greenhouse2030: Sustainable cultivation with a future' is funded by the Ministry of Agriculture, Nature and Food Quality in collaboration with the Greenhouse as Energy Source program.

Source and Photo Courtesy of Wageningen University & Research

Source: Wageningen University & Research