Tomatoes (cv. Boris) were grown in two unheated greenhouses, a Venlo type glasshouse with automated ventilation and a standard Colombian plastic greenhouse with fixed open ridge and manual sidewall ventilation. During the night a plastic thermal screen was used in the plastic greenhouse. The average day temperatures were 18.2 °C and 19.0 °C for the plastic greenhouse and glasshouse, respectively. During the night the average temperatures were 12.1 °C and 12.4 °C. Due to the heavy structure of the glasshouse, light conditions under plastic were about 10 % higher. Despite this higher light intensity in the plastic greenhouse, no important differences in total DW were found between greenhouses. The time evolution of the DW of the leaves showed a sharper rise in the plastic greenhouse, together with a slower DW (FW) accumulation in the fruits. The total DM partitioning for the plastic greenhouse resulted in more leaves and less fruits when compared to the glasshouse. This resulted for the glasshouse in 27 % more FW in fruits for the growing season. The node appearance rate was 2.38 and 2.27 days per node, for the plastic and the glasshouse respectively.

It seems that in the Bogota Plateau a better temperature regime is preferable over higher light conditions for the cultivation of tomatoes.