Production and laboratory greenhouses

And not only that, but the cultivation of certain vegetable and fruit species or varieties in regions that may be climatically unfavourable is often made possible in the first place. With the flexible constructions made of steel, aluminium and glass, the trio of sunlight, heat and humidity required can be controlled very well, and the harvest can be harvested safely against all weather conditions.

By the way: The same technical and constructive aspects apply to the particularly flexible laboratory greenhouses of research institutes as to professional horticulture.

Over the decades of experience of mainly Dutch gardeners, three types of construction in particular have prevailed for professional greenhouses:

The typical Venlo greenhouse with rows of caps in block construction, and thanks to the lattice beam large spans and approx. 4 to 10 m standing wall height.

The convertible greenhouse modified on this basis, which enables increased ventilation performance for the desired hardening of plants with roof elements that can be opened completely and functions as an open-air greenhouse in good weather.

The wide-nave greenhouse, which offers more freedom for installed infrastructure such as shading and irrigation systems with very wide lattice beam widths of up to 16 m and 12 m high supports.

As glass for the side walls, 4 mm thick float glass with about 89% light transmittance is still the standard – in individual cases, a special coating is applied to the inside against moisture, as fogged up panes also reduce light transmission. Much more critical for fruits and plants, however, is the glass covering, through which sunlight and heat mainly reach the greenhouse. Here, too, 4 mm is the common dimension, but in general there are two goals here: maximum light input, as well as the widest possible scattering of natural light so that the plants are homogeneously illuminated and thrive optimally. Here, too, float glass is often used, if necessary. in summer, the light is scattered with shading paint applied on the outside. White glass with reduced iron oxide content and optional anti-reflection coating of the lenses (on one or both sides) promises 2 to 3.5% more plant growth. Diffuse glass is either the corriggled “garden clear glass” (DIN 11 526) with its uneven underside, or specially structured, prismed glass with a defined “haze” factor of up to 70%. With the widely scattered light, the light penetrates deeper into the crop, and a larger leaf surface is illuminated, thus enabling stronger photosynthesis. Whether the lenses are hardened or not is more a matter of weighing up the regional weather risk against the additional financial outlay.