when to take orchids indoors

[Liz]

I just did some weather research and found that the average lows here are about 54, 49, 49 and 51 for November, December, January and February. That's not too bad. I wonder if I can get away with moving everything onto the dining room table when it's supposed to get really cold (sorry, to those of you in Michigan, etc.) and leave them outside during the days and warmer nights?

Any thoughts?

[Tanya]

Winters in Hong Kong are mild, but it sometimes go as low as 50's or lower. When that happens I bring the smaller ones indoors if I can find a space for them which is not easy considering the kind of housing we have here. The rest I just wrap them with clear plastic bag but only if its windy. Make sure they are dry though. Someone told me before that its not the cold temp that kills, its the cold dry wind. So even if its in the 50's I wouldn't worry much about them if its not windy. The vandas can withstand being outdoors also provided they were given time to acclimatize. If not, bag' em. Having said, don't take risk with plants that didn't had time to acclimatize to the cold. Bring them indoors.

Tanya

[LJA]

Unless it's a standard cymbidium, anything lower than 49 for a tropical orchid is looking for trouble. 55 is really the lowest you should allow them to stay in, and that's plenty low to induce spikes on those plants that need a good 20 to 25 degree difference in temps to bloom. I keep the greenhouse at 59-60 in the winter, and there's enough "microclimate" near the cool cell (where it's not insulated) that the paphs there that need it get the spike-inducing dip down to 55. It's already hitting 60 here at night, and local conditions can be very different than published averages for a region. Don't wait too long, and be sure to spray / run insecticide through the medium to keep any kind of infestation from starting up indoors.

[Cinderella]

Louis are you meaning 55 for one night or are several nights of 55 okay and then bring them in?

[LJA]

If you can *guarantee* that it won't get below 55, you can leave them out. I can't guarantee that here, so once night time temps start to go below 60, anything outside comes in. All it takes is one cold night in the middle of all the warmer ones to really set the plants back, and too much effort has gone into raising them to risk that. 55 is the lowest I would let them stay in for any length of time, night after night.

Like Tanya said, if you suspect it might get into the lower 50s but you can't bring the plants in right then, a plastic tarp wrapped around and over them is usually enough to insulate them that one time. (Take it off in the morning before the sun hits, or the plants may cook....)

[e.muehlbauer]

I leave my orchids out as long as I possibly can. Most years, I don't bring them in at all until the end of September, when temperatures begin to drop below the 60's here in NYC. I bring them in in succession as temps drop through October into November. First of course are the warm growers...my Ascocenda, phal-type dends, Oncidiums and some of the paph seedlings, some of the Maudiae-types..some of the phrags also. This is when I put my very few remaining phals outside- I find phals outdoors are slug and snail magnets, so I only put them out for about 2 weeks or so to get a chill in the high 50's (they still won't bloom for me...too much of a paph grower to really care). Through October as temps move into the lower 50's I start to bring in the catt's...beginning with BLC's and ending with SLC's. The complex paphs and insigne type species will also come in...a shame, because the indoor warmth tends to blast the developing buds...my cool room hasn't had a chance to get cool. By the end of the month all that is left outdoors are the parvi's like armeniacum, some of the Masdevallia's, and some of the cymbidiums and nobile dend's. I bring in the last ones when there is a risk of frost, or when temps are predicted to go below 39. Regardless, as the first frost sometimes hits NYC as late as mid-Dec, I reluctantly bring in the last stragglers by Mid- Nov, to avoid the risk of problems. While I have dealt with plenty of heat damage, I have only seen cold damage on 2 orchids....interestingly enough, a paph hirsutissimum and a Masdevallia veitchiana, while temps were still in the upper 40's. I have seen my parvi's covered by surprise snowfalls, which have left them without any damage at all. The biggest problems come with bud blast when bringing plants indoors...my cool room won't drop into the 50's until the outside temp is in the low 40's....its a part of my house, not a greenhouse. Take care, Eric Muehlbauer