GREENHOUSE CONSTRUCTIONS FOR SMALL SCALE FARMERS IN TROPICAL REGIONS

Abstract

The Food and Agriculture Organisation of the United Nations, FAO, supported some projects for the improvement of vegetable and flower production for small scale farmers in tropical regions by protected cultivation in greenhouses. The overall aim is to improve the food security status as well as the socio-economic well being of the poor. The general design criteria for greenhouses are: The climate conditions in the region and climate control, the general design requirements for plastic film greenhouses, including standards if available, the locally available cost effective materials and life cycle. One has to distinguish tropical highlands and tropical lowlands for tropical climate: If the mean minimum outside temperature is lower than 12° C, lockable ventilation openings have to be installed. With mean minimum outside temperatures above 12° C, ventilation openings can be permanently open. One can assume that ventilation openings are necessary with mean maximum temperatures above 27° C in multi span greenhouses. Tropical regions have heavy rainfall and storm very often. The greenhouse construction has to withstand those weather conditions. In order to minimise the cost of construction, the use of locally made material and skills is recommended. The promotion of greenhouses in the tropical regions is considered as a component of a broader approach for integrated Production and Protection management with the final objective of reducing the spraying of pesticides and increasing crop production all year round. Nets in front of the ventilation openings are necessary in many regions. But nets reduce the ventilation efficiency remarkably.