DAN IEL RYERSON BOX 805 HOMESTEAD, FLORIDA 
eB RAI 
| RECEIVED 
* MAY29. 1952 * 
DRY CULTURE MEDIA FOR PLANTING ORCHID SEED 
(Modified Knudson Formula) 
INSTRUCTIONS FOR USE OF MEDIA 
fe re: Pe ee RT 
This dry media is complete with nutrients, sugar and agar. BUT DO NOT TRY TO USE 
FRACTIONAL AMOUNTS OF IT. THE VARIOUS INGREDIENTS BECOME UNIFORMLY MIX®D ONLY 
WHEN IN SOLUTION, 
Heat one quart of distilled water in an enamel saucepan until it is steaming but 
not at the boiling stage. Stir in the dry media and continue to heat to near 
boiling, stirring frequently. Do not allow mixture to boil rapidly, as the agar 
will tend to stick to the bottom and scorch. Keep scraping it from the bottom of 
the pan as you stir. 
It will require about $ hour for agar to dissolve completely. It should be not 
only clear, like peletings but lumpless. 
Clear glass pint bottles, such as those that contained syrup or cooking oils, make 
good flasks and are easier to store than the convential Erlemeyer flasks, as 
they can be stacked in a rack, conserving greenhouse space. However, these bot- 
tles must be thoroughly cleaned and scoured. Then rinse, first with hydrochloric 
acid to remove any alkali, then with distilled water. 
When the agar is dissolving, you can be preheating the oven to 225 degrees F. and 
also preheating the clean, dry bottles, so they will not break when the hot agar 
is poured into thom. 
STOPPERS - Strips of sterile cotton about 3" x 13" can be tightly rolled into 
scoppers that fit the necks of the pint bottles. Most instructions say to drip 
copper sulphate solution on the protruding part of these stoppers after the seed 
planting is done, but I have found it better protection to saturate the stoppers 
and dry them out thoroughly in advance of the agar preparation. They should be 
formed and dried in the necks of bottles identical to (but not the SAME bottles) 
those used for the agar. Any contact between the agar and the copper sulphate 
would kill the seed to be planted on the agar. 
I like to keep a set of stoppers drying in the necks of bottles that are reserved 
for that purpose only. This drying process will require several days at room 
temperature. It can be done more rapidly in a warm oven (set at as low tempera- 
ture as possible). 
PROCESS ING THE AGAR - When the simmering agar is thoroughly melted, pour about 
three ounces of it into each of the ten clean, heated bottles. If there is a 
little of the solution left, distribute it among the bottles. 
Twist the prepared stoppers into the necks of the bottles, and place them in the 
preheated oven (225 degrees). Leave them there to cook for exactly $ hour. 
Remove the bottles from the oven to a rack, asbestos pad, or top of oven, to cool. 
Do not place on cold surface such as sink, or they will break. Allow to cool 12 
hours. Then return to oven (250 degrees this time) and reprocess = hour. 
When bottles are removed the second time, lay them levelly on their sides and 
allow to cool in that position. When agar is firm, it will be ready for planting. 
Planting instructions are on Page B. 
