The BEST (Bubble Energy Saving Technology) greenhouse is a remarkable construction: a semi-curved span with bubble wrap, thus resembling a combination of a tunnel greenhouse and a wide-span greenhouse. Previous research has shown that woody soft fruit can be grown well and energy-efficiently in the BEST greenhouse. The Business Unit Greenhouse Horticulture and Flower Bulbs of Wageningen University & Research started research in the spring of 2021 into the possibilities of the BEST greenhouse for growing courgettes.
The aim of the BEST greenhouse is to save energy and limit CO2 consumption. The bubble wrap provides a diffused light. To prevent the temperature from rising too much, the greenhouse is equipped with continuous ridge aeration, and the side walls can largely be opened. The BEST greenhouse is also equipped with a screen, high-pressure atomization, a CO2 dosing installation, and heating.
The cultivation of raspberries and blackberries in the BEST greenhouse has been studied in recent years as part of the Kas Als Energiebron (Greenhouse as Energysource) program. The main conclusion of that research is that the greenhouse ensures good production with approximately 40% energy savings. Zucchini, like the woody berries, needs a moderate amount of heat and is therefore often grown outdoors, but the yellow courgette, in particular, is vulnerable to wind and is actually only grown in a covered environment. That is why WUR investigates whether the cultivation of yellow zucchini is also feasible in the BEST greenhouse.
65 fruits per year
The research consists of two crops. The first crop was from February to July, and the second started in August. The results of the first cultivation are very positive. For example, 65 fruits per square meter were harvested; the expectation was that 75 fruits per year would be possible. Those 65 fruits are therefore relatively high compared to the production on a practical farm.
In that first cultivation, 5 kilograms of CO2 per m2 was required for cultivation; that is half of the expected 10 kilograms for two crops. The use of natural gas was slightly higher than expected - partly due to a cold period - namely 7.7 m3 gas per m2 (the expectation was 10 m3 in two crops). The second crop is expected to continue into November, when the final figures will be announced.
For more information:
Wageningen University & Research
www.wur.nl