Greenhouse tomato production is discussed under the following topics: importance of the industry, costs of production, greenhouse structures, cropping schedules, transplant production, plant spacing and extra stems, cultivars, crop management (training systems, side-shooting and trimming, pollination, de-leafing, fruit pruning and development, topping plants at the end of the crop), substrates and substrate systems, nutrition and irrigation (nutrition, controlling growth, recirculating systems, irrigation), environmental control (relative humidity, temperature, carbon dioxide, light intensity, air pollutants, pest and disease management - insect and disease problems, biological control, biopesticides, conventional pesticides, cultural practices to avoid insect and disease problems, diseases in the root environment, root grafting), marketing, harvest, postharvest packing and storage, and potential production.

The closed greenhouse is a recent innovation in the horticulture industry. Cooling by ventilation is replaced partly (in semi-closed greenhouses) or completely (in closed greenhouses) by mechanical cooling. Excess solar energy is collected and stored to be reused to heat the greenhouse. In temperate climates, this concept combines improved crop production with energy savings. This paper presents an overview of climate, crop growth and development, and crop yield in closed and semi-closed greenhouses. The technical principles of a closed greenhouse are described and the macroclimate and microclimate arising from this are studied. The consequences of the typical growth conditions found in closed greenhouses for crop physiology and crop yield are examined. Finally, the experiences of commercial growers are presented. In temperate climates, closed greenhouses can reduce the use of fossil fuel-derived energy by 25 -35%, compared with open greenhouses. With high global radiation, the climate in closed greenhouses is characterised by high CO 2 concentrations, high air humidity, improved temperature control, and a vertical temperature gradient. An annual increase in production of 10 -20% is realistic, with reduced amounts of supplied CO 2 . The yield increase is primarily obtained through increased rates of photosynthesis due to the higher CO 2 concentrations in closed greenhouses. To introduce this innovation into practice, knowledge transfer was a key factor for its implementation and the realisation of increased production levels. Future trends will require minimising the use of fossil fuels and increasing the level of control of the production process. Closed and semi-closed greenhouses fit seamlessly into this trend as they allow for a more controlled climate and higher levels of production, combined with savings in fossil fuel use.

No abstract

A (semi-)closed greenhouse is a novel greenhouse with an active cooling system and temporary heat storage in an aquifer. Air is cooled, heated and dehumidified by air treatment units. Climate in ( (55 kg m -2 ), respectively. Cumulative production in the closed greenhouse was 14% higher than in the open greenhouse in week 29 after planting but at the end of the experiment the cumulative increase was only 4% due to botrytis. Model calculations showed that the production increase in the closed and semi-closed greenhouses was explained by higher CO 2 concentration.

In 2002 tomato was cultivated in a closed venlo-type greenhouse to investigate the influence of cooling with forced air movement along heat-exchangers combined with high CO 2 level under summer light conditions on production and quality. Transpiration in the closed greenhouse with forced air movement was, compared to a conventional greenhouse, higher at low light levels (2 instead of 1 kg/m 2 ) and lower at high light levels kg/m 2 (4 instead of 5 kg.m 2 ). Comparison of the observed yield with crop yields predicted with TOMSIM showed that yield was increased by 22% from 46.2 to 56.2 kg/m 2 compared to a conventional greenhouse with CO 2 concentration always above 500 ppm. The higher CO 2 concentration in the closed greenhouse (always 1000 ppm) could explain only a 9% yield increase.