bright days in summer in most parts of the country, and near 65° at night. 
This is a safe temperature for California through the year. In the North- 
ern and Eastern states, winter temperature may range from 65° to 75° mid- 
day and in the low 50’s at night. Some growers have good luck with even 
lower temperatures, and if you are one of them so much the better. The 
important thing to remember is that if the day temperature is low then 
that at night should be lower; if the day is warm then the night temp - 
erature should be up a little. A good guide for humidity is that an Orchid 
house should be comfortable to people all the time they are walking in it, 
but if one stands still for a few minutes, they should perspire a little. 
Quoting figures again, from 50 to 70% relative humidity in day time, and as 
far below 100% at night as is possible without using a lot of artificial 
heat. With this much information, the problem of ventilation is solved 
before it arises. 
The subject of when to water and when to withhold water from the grow- 
ing media of Orchid Plants has been a much mooted question for many years 
gone by, so the best that one could hope for in any set of cultural in- 
structions would be to accomplish some alleviation of the fear of attacking 
this task. The degree of dryness the growing media should reach before 
water is applied to it may be determined in many ways; by hefting the pot 
and determining the dryness by weight, or lifting it up completely and 
looking at the crock at the bottom of the pot, and if this looks dry, water 
and if not, LEAVE IT ALONE!!! Forget about it! Never inspect the same pot 
twice in one day for dryness. Look at it and enjoy it, sponge the leaves, 
look for bugs if you will, but forget about watering for at least four days 
after one inspection. Be careful with big pots ... 5%" and 6" ... water 
them two or three days after you think they need it. To a certain extent, 
Cattleyas are camels. There is a little trick invented by one of our local 
amateurs for determining the dryness. She used a bridge pencil, sharpened 
with a pencil sharpener, pushing it into the growing media and, if on re- 
moving it the roughened wood looked moist, she left the plant alone, and 
if it looked quite dry she watered the plant. 
Potting should be demonstrated. The only advice I would give is to 
pot your plants firmly and at the first sign of satisfaction that you have 
done a good job, leave it alone. Don’t poke it, jab it, or feel it, or 
worry about it. Most people do a guod potting job and then spoil it by a 
few extra touches here and there. We hear a lot about growing mixtures 
these days. No doubt they all have their merits, but we feel that osmunda is the 
safest and cheapest in the long run. A spraying program every month or so 
with one of the commercial Orchid sprays will provide adequate pest control 
These notes are basically for Cattleyas, but thousands of amateurs 
throughout the nation have demonstrated that Cypripediums, Phalaenopsis, 
Dendrobiums and many other Orchids and other plants will grow side by 
side under conditions similar to these described here. 
We hear a lot about light control, temperature control, and lots of 
other controls.....all of them are important, but most important of all is 
Self Control!! 
