The large vegetation of both zones – the always damp and the periodically damp – also acts on the orchids. The trees and bushes of periodically humid areas are partly. subject to leaf fall. This means increased exposure to light for the epiphytic growing orchids, because the dry season doesn't bring any – like our winter - a shortening and diminution of the incidence of light. We can see the transition to a subtropical climate from the extension of the rest period, the hardness of the growth, decreased general sensitivity, often particularly high lighting requirements and other phenomena. With them a very extensive adaptation to the climate is achieved. That also includes, that the plants, when they are idle, temporarily tolerated low temperatures down to about minus 5 °, without causing damage.
The environmental conditions are expressed in the habit of the plant, and we have to learn, read their claims from it. In addition to the climate, the altitude also plays an important role as an environmental factor. As the altitude rises, the temperature drops, and so is not just important to know, the geographical latitude at which an orchid site is located, but also in what amount.
The condition of the soil, another important factor, only plays a decisive role here for terrestrial orchids. However, the nature of the soil is indirectly of a certain importance for the design of the large vegetation, the epiphytes depend on their more or less large presence.
The organs of vegetation provide indications of the light requirements, so the pseudobulbs and leaves. There are many transitions; the following points are essential:
Ground dwellers: no bulb formation, Leaves relatively soft. Expectations: no direct sunlight, lots of shade and moisture, no rest period. example: Paphiopedilum.
a) Leaves extensive, fleshy, no bulb formation. Expectations: no direct sunlight, lots of shade, no rest period. example: Phalaenopsis.
b) Leaves extensive, thin, Bulbs very pronounced,Leaves are shed at the end of the growing season. Expectations: Penumbra, a lot of moisture, Rest period strongly pronounced, complete dehydration. example: Calanthe of the deciduous section, Catasetum.
c) Leaves more or less coarse over a large area, Bulbs more or less pronounced, elongated, plump. Expectations: Penumbra, much light as the bulbs begin to ripen, Abundant moisture in vegetation, Rest time shorter or longer, moderately moist, Avoid shrinking the bulbs. example: Catt-leya, Laelia, Stanhopea, Lycaste, Odontoglossum, Oncidium, Cymbidium and many others.
d) Leaves narrow, rough leathery, no bulbs. Expectations: lots of light, a lot of moisture in vegetation, Rest time pronounced. example: Vanda coerulea, V. tricolor and others, Listrostachys, studarettia, AERIDES, Board flash andere.
e) Leaves almost terete, rinnig gircht, no bulbs. Expectations: strongest light, shadowless when used to, a lot of water during the growing season, Rest time pronounced. example: Vanda teres, Renanthera and others.
With these examples it was shown, how the light factor visibly affects the plant. Unfortunately, the demands on temperature and humidity are not so easily or not at all apparent from their exterior. They can only be derived from the climate rhythm of the home location.