In this discussion we answer a few basic questions about orchid 
culture by briefly discussing the most important factors of the 
environment that influence the growth of orchids. Since climatic 
conditions vary a great deal from place to placeandat different 
times ofthe year, specific instructions are inadvisable. Rather, 
it would profit the grower to gain an idea of how various factors 
affect plant growth and how they are relatedto each other. Thus, 
he will be able to act intelligently, to analyze any problem that 
may arise, or to interpret any recommendation as they applyto 
his own situation. 
Repotting is specifically described to serve as a guide for 
beginners. 
Reference may be made to some of the fine books on orchid 
culture listed in our bibliography. 
Water 
Water is used by plants in the manufacture of plant food, in 
transporting the food to various parts of the plant, and to keep 
the plant erect by making the cells turgid. One can very well 
imagine what would happenif a condition of water deficiency 
should occur. The cell walls would lose their rigidity, leaves 
and pseudobulbs would become shriveled, and the manufacture 
and transport of food would cease. Growthand development would 
be slowed down considerably and eventually cease. 
Roses, chrysanthemums and many other garden plants wiltas 
soon as water becomes unavailable. With Cattleyas, onthe other 
hand, the effect of insufficient water is not immediately obvious, 
although internal changes may have occurred. The effect of lack 
of water is not immediately shown by the succulent and much- 
thickened pseudobulbs and leaves. Drying the osmundine thorough- 
ly between applications of water could actually be harmful to the 
growth of Cattleyas. 
Most of the water loss from plants is lost through transpiration. 
Transpiration simply means the loss of water from plant tissues 
in the form of water vapor. In determining the frequency of 
watering, the factors affecting transpiration should be considered. 
These are discussed in the following pages. 
