CULTURE NOTES
BY
The climate in Richmond, California is typically coastal with mild winters, warm springs, sometimes overcast in the summer time with a hot dry fall. It is usually breezy, and the wind usually picks up in the late afternoon. Every seven years, we experience two to three nights of freezing-cold weather. Then all of us orchid growers rush to get our plants under cover or inside the home.
MATURE CYMBIDIUM orchids are grown outdoors under full sun from winter through early spring, then under 70% shade cloth until late fall. The usual breezes tend to prevent leaf scorch on unprotected late-season plants. Younger Cymbidiums are grown under shade cloth year-round.
TROPICAL ORCHIDS are grown in an unheated 6í x 16í lean-to fiberglass greenhouse. It has a laid-brick floor and a 175 gallon hot tub both of which provide mass (heat storing volume). The hot tub is usually tightly closed and does not affect the humidity in the greenhouse. It only gives off gentle heat through its insulated sides. The brick floor, however, since being watered daily for a year, now seems to keep the humidity at 60% on all but the hottest days.
PHALAENOPSIS are grown inside the house year around on East and South facing windows.
In the winter months, short days are supplemented with fluorescent lights for the younger plants. The thermostat is set at 58 deg.F. and windows are often left open during the warm months. Some plants will then experience a night drop to 55 deg.F. This seems to initiate spiking.
TEMPERATURE in the greenhouse in summer and fall regularly go to 90 to 100 deg.F., with night temperature falling to 60-55 deg.F. Cooling is accomplished by the use of a large fan, extra layers of shade cloth and extra misting.
In the winter, sunny days keep the greenhouse at 70 deg.F. but night temperature may fall as low as 45 deg.F. At this point, an electric, oil-filled radiant heater is set up at night in the greenhouse to keep the temperature above 45 deg.F.
Note about the author: O.S.C. member Paula Shiu is an enthusiastic grower and has won a number of ribbons and trophies for her plants and displays at Society Shows.