Temperature

I'm cursed by living in a temperate climate.

Dry, but temperate. Its the dryness that makes me keep my orchids in a greenhouse.

I don't know what happened this year but my greenhouse hasn't been getting much lower than 61-62F at night. I have a Radio Shack thermometer that reads an indoor/outdoor temps. The outdoor sensor is in the center of the greenhouse (GH).

My first thought was that the GH sensor had gone bad after years of accidentally getting watered on, so I replaced it. While that did make a slight difference it wasn't one that was outside the accuracy range for the instrument (I think most of these have a degree of accuracy to within 3-4 degrees). Additionally, the min/max mercury thermometer gives the same readings: no more than 60-61F at night. And this has been going on all 2009; winter, spring and summer.

I'm triplely cursed by being a bookish sort of person, having a decent library and by reading too much. Back in the 1950s Gavino Rotor did a study on daylength and blooming but also on *temperatures* and blooming. He used cattleyas, and since that's mostly what I grow I take this study to heart. In it not only does daylength affect bloom time, but night time temps did too. Anything around 62-63F delayed blooming.

ACK! That's right where my GH is.

In our county (Eastern San Francisco Bay Area) many people can grow orchids very well outside. Except for the ambient humidity. Which is why I have a GH - to trap the humidity. But now I'm beginning to wonder.

Rebecca Northen had great photos of her lathe house in her book Home Orchid Growing. Maybe that's all I really need. Replace the side panels with screening so the air comes through, removing heat, (also removing humidity) but put in a sprinkler system similar to Marilyn Mirro's method for growing Vandas outside in Massachusettes. Better air flow, better air quality, better diurnal temp variation.

Granted the humidity would be very close to ambient, but ?????

Idunno. I'm stymied by my choices. Like a deer in the headlights. [sigh] But I'm getting tired of failures to bloom. I guess I have to get up the energy to address this.

Just another opportunity for personal growth.