Orchid Flasking Temperature: 72–75°F Ideal for Seed Germination

A friend in Australia runs a home lab at 22°C (72°F) for Phalaenopsis flasking; after 10 weeks, no germination—some flasks contaminated. He suspects temperature is too low for tropical orchids.

Expert Temperature Recommendation

Flasking at room temperature (72–75°F) is standard. Rebecca Tyson Northen's Home Orchid Growing confirms: Cattleya seed germinates best at 70–75°F day/night; night may drop to 65°F. Fluctuations >10° retard growth.

Light & Other Critical Factors

• Light: Flasks 12" from two 40W Gro-Lux tubes (~200 foot-candles).
• Seed viability: Check under microscope before sowing.
• Medium type & sterilization method: Both affect success.

Recommend Northen's book for detailed protocols.