The Orchid Doctor Articles under the Heading Photoperiodism

Photoperiodism Comments
PHOTOPERIODICITY: Affected by Use of Electric Lamps A green lamp of low wattage can be used for working at night in a greenhouse; moderate light for about two hours before 10 o'clock or 11 o'clock has little effect, but more effect if burned in the middle of the night. A69-242; refer also to A61-106 0
PHOTOPERIODICITY: In Cattleyas Plants set their buds in a certain daylength; artificial light in a living room where plant is growing lengthens the day and prevents bud set. A70-344 0
PHOTOPERIODISM: Effects of Day Length At three degrees north of the equator the difference between the shortest and longest days of the year is 20 minutes yet orchids bloom seasonally. A61-105 0
PHOTOPERIODISM: Hours of Complete Darkness Needed by Cattleyas There is no generally recognized rule-of-thumb; in general 12 to 15 hours tend to favor flowering; eight to nine hours tend to stimulate vegetative growth; some summer-flowering cattleyas fall between the two. A64-1074 0

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  1. John Small asked question Which is correct? in category General Discussion
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  3. Debbie Chase asked question Help to Identify Orchid in category General Discussion
  4. Colin Campbell asked question Unmatched Oncidium Alliance Orchid in category General Discussion
  5. Maria Delaney asked question Double spikes on oncidiums in category Oncidium Alliance

New Comments

  1. Debbie Chase commented on topic "Help to Identify Orchid " by Debbie Chase
  2. Tien Pham commented on member plant V. Yip Sum Wah 'Flame' by Tanya Lam
  3. Carol Holdren commented on topic "Can someone give me the name of this orchid?" by Jean Seymour
  4. Carol Holdren commented on member plant Spathoglotis plicata (Ground Orchid) by Frances LaVigne
  5. Frances LaVigne commented on member plant Grt. Rosy Jewel var. alba by Frances LaVigne
  6. Barry Mellefont commented on article "ANTS: Nesting Between Osmunda and Bark Slab Requires Control Safe for Visiting Hummingbirds" by Robert M. [Bert] Hamilton (Compiler)
  7. Alex Maximiano commented on topic "Unmatched Oncidium Alliance Orchid" by Colin Campbell
  8. Carol Holdren commented on member plant Bc. Jairak Kiku 'Jairak kiku' by Frances LaVigne
  9. Frances LaVigne commented on member plant C. purpurata var. (flammea x sanguinea) by Carol Holdren
  10. Frances LaVigne commented on member plant Ascda. Kulwadee Fragrance by Frances LaVigne