Science - September 9, 2011

Simple greenhouse for growing vegetables in the tropics

Indonesian market gardeners can get far better yields by buying a relatively simple greenhouse with a plastic roof and extensive natural ventilation. This kind of greenhouse is also suitable for tropical lowlands in other countries, argues the Indonesian researcher Impron in his PhD thesis.

Vegetable yields under tropical conditions are often disappointing because of the heavy rainfall and the diseases and pests in the warm, humid climate. Yields could be increased substantially by growing the vegetables in a greenhouse.

Impron used models to analyze the effects of the tropical conditions on crops and the greenhouse climate. Then he carried out practical experiments with different types of greenhouse in the production of tomatoes sold on the vine. The critical factors turned out to be considerable ventilation capacity to reduce the humidity and temperature in the greenhouse, and having a plastic film on the greenhouse roof to limit infrared radiation. Expensive cooling systems turned out not to be necessary.
The greenhouse was specifically designed for tropical lowlands by Wageningen UR Greenhouse Horticulture. Another advantage of this 'adaptive greenhouse' is that it is mostly made from materials that are available locally.

Impron, whose supervisor is Gerard Bot, emeritus professor in Applied Physics, will receive his doctorate on 12 September. His research is partly funded by the Ministry of Economic Affairs, Agriculture and Innovation. The Indonesian adaptive greenhouse was built by the Dutch company Roveno Systems, and the plastic film on the roof by Oerlemans Plastic. Companies supplying the Dutch horticulture sector often invest in research to provide customized products for the international horticulture market