Light
Most orchids do well in indirect sunlight. Indirect means that there is something in between the plant and the sun to scatter or block light, whether it be shadecloth, a sheer curtain, a layer of plastic or fibreglass sheeting, and so forth.
There are many cases where direct sunlight is just fine, as long as the plant has been conditioned to the light. Many popular orchids like cattleya, dendrobiums, cymbidiums and some oncidiums are happy in direct winter/spring sun as long as temperatures are on the low side and there is air movement to cool the leaves.
Summer/autumn on the other hand, it can be sometimes too hot and too dry, resulting in burned leaves, not that burned leaves on their own can kill an orchid. One thing to watch is that if the leaves do get burned, a secondary infection (such as bacterial or fungal rot) can kick in, you have to be very careful with watering (waiting until temperatures have dropped) and airflow (keeping damaged tissue dry).
Sometimes orchids just won’t bloom without the excessive sun. Most growers often say the right amount of light is the highest amount of light you can give without burning the plant. The colour of the leaves is a good gauge of this, each orchid’s different so what you should be looking for is:
- Pale green or green/yellow
- Hints of red or red spots on leaves
- Hints of yellow on leaves
Leaves shouldn’t be dark green, and if they are, you’ll need to acclimatise the orchid to more light by putting it in progressively lighter situations, like starting it in a darker part of the growing area and moving it a little closer to a lighter part of the area.
On that subject the growing area should have parts that receive different levels of light, most growing areas naturally have this due to the movement / position of sun during the day, and effect of other structures surrounding the growing area. If not, set up some spaces using shadecloth or other shade cover, you can even use taller plants as shade for others.
The other thing to watch is that (unless you live on the equator), parts of the growing area will receive more sun depending on the season; summer sun comes from the nearest pole (e.g. south in southern hemisphere) and winter sun comes from the equator (e.g. north in southern hemisphere).
