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CARE OF ESTARLISHED PLANTS 
Ce ee 
1, Temperature 
In general for the various’ types of orchids the temperature requirements 
are divided into four divisions, although these exact divisions are not neces= 
sarily always followed in commercial orchid growing or in growing orchids out 
doors in Florida, California and Texas, 
A. Tropical House . 
A night temperature of above 65°, preferably 70° should be maintained, 
In the winter the day temperature should be 70 to 45°. Phalaenopsis, 
Vandas, Aerides, Arachnis and a few Oncidium species are grown at this 
temperature. 
Be Cattleya House 
A night temperature of 60 to 65° should be maintained, All ocattleyas 
with the exception of C, Citrina should be grown at this temperature, 
Also Brassavolas, most South American Laelias, some Oncidiums and pratie 
cally all Dendrobiums may be included, The day temperature in the winter 
should be 65 to 70°, 
C, Intermediate House 
A night temperature of 55 to 589 and a day temperature of 58 to 60°, 
Odontoglossum Grande, and a number of the Oncidiums, Miltonias and hybrids 
of these and Odontoglossums will do well at this temperature, In recent 
years some orchid growers have combined the orchids that were grown in 
the Cattleya House with those in the Intermediate House considering all 
as Intermediate, The orchids listed under "B" will stand a night temper~ 
ature of 5° lower than is listed and can be sucessfully grovm in one 
houses 
D. Cool House 
night temperature of 50 to 55° and a day temperature of 55 to 60°. 
All Columbian Qdontoglossums should be grown at this temperature. Most 
Odontoglossums cannot stand high temperatures and unless a cool temperae 
ture can be maintained one should not attempt to grow the cool types of 
this genera, Cattleya Citrina and the Mexican Laelias also do well at 
this temperature, although they are often grown as intermediate, 
In the summer the cool orchids should be kept below 90° Fahr, and the 
intermediate and tropical orchids should be kept below a temperature of 100° 
Fahr,, although short periods at slightly higher temperatures will not cause 
harm, In order to keep orchids that are growing in a greenhouse at the dee 
sired temperature the ventilators must be opened wide on hot summer days. 
oe Humidity 
Every effort should be made to maintain relative humidity above 65%, 
particularly with higher temperatures, Opening the ventilators causes the 
humidity to drop, so in the summer the plants should be sprayed several times 
a day, In the winter months when the sun shines, one spraying a day is suf» 
ficent. On cloudy days the plants should not be sprayed unless they are very 
dry. In order to keep the humidity up on cloudy days the walks and soil under 
the benches may be sprayed. In the greenhouse the benches may be constructed 
