1606 THE ORCHID ‘REVIEW. [JUNE, 1923. 
ORCHID CULTURE IN DENVER, COLORADO, U.S.A. 
By WILLIAM _B. BERGER. 
T may be of interest to readers of the Orchid Review to learn about the 
culture of Orchids in Denver, Colorado, where the climate is’so different © 
from that of England and even from that of the eastern part of the United 
States. Here, at an elevation of a mile above sea level, and with extremes 
of temperature ranging from 95° or so in the summer to an occasional 15° 
below zero in the winter, it may seem presumptuous to attempt it at all. 
But perhaps if one can make the greatest use of the advantage of an 
almost unlimited supply of bright sunshine and fresh air, something may be 
accomplished. And by the judicious use of shading it ought to be possible | 
to get the right light conditions the whole year through. 
The greatest difficulty seems to be the lack of humidity in the atmos- 
phere. In spite of constant damping down and of pans of water with 
cheese-cloth suspended in them in front of the bottom ventilators, it is very 
difficult to keep a nice atmosphere in the house when the humidity outside 
is only about 15 per cent. Of course, it is not always so dry, once ina 
while we do get a damp day, but as a general thing it is a constant struggle 
to keep up the humidity. 
As for the elevation above sea level, I do not believe that of itself makes 
any great difference. At first, when I read of the altitudes at which some of 
the Odontoglossums grew I thought they would be just the plants to thrive 
here, but after some years of effort I now know better. Only by keeping 
them in the very dampest portion of the house will they do anything at all. 
Odontoglossum citrosum is an exception, and does well suspended near 
the glass. 
The Cattleyas do not seem to mind the dryness so much, and succeed 
fairly well; one Cattleya hybrid last spring had eighteen splendid blooms. 
The Cypripediums are another hard problem, and as for the Dendrobiums, 
the Cymbidiums, and other plants from the eastern hemisphere, I have not 
so far been able to get them to grow very successfully. Ihe Mexican Lelia, 
however, really does seem to like growing here, and is by far the easiest to 
keep in good condition. As an example of how the members of this genus 
like the climate, a plant of Lelia anceps last summer sent up two strong 
flower stalks. One of them immediately started blooming, and for four 
months one after another of the lowest buds on the stalk bloomed, at tle 
same time the upper buds were developing, and finally, about Christmas, the 
three end buds opened, all fine flowers. Lelia purpurata is also a good 
grower and blooms very freely. 
Altogether, climatic conditions make Orchid culture here a very interest- 
ing problem, I believe an experienced grower, making the most of the good 
