Moving Orchids Outside After Summer Heat
 

I'm wondering when/if I should move some of my orchids outside after the intense summer heat we have had in East Texas. Most of mine are Phals, a few are Cattleyas and 1-2 Epidendrum. They have been in my sunroom all summer with lots of windows and I keep a misting humidifier and a humidity tray going, as well as a ceiling fan on low. I know that some orchids need a change in temperature to encourage growth. So, if I should move them outside during day or nighttime this Fall, what would be the ideal conditions, temperature, etc.

Nana Trish, I put part of my collection out as soon as the rains started. I leave them out all the time. If it rains, they get a lot of water. If it doesn't, I help them along by watering them. I have phals, some dendrobiums, a couple of oncidiums, a encyclia and a couple of laelias (struggling!) in the shade in a sheltered patio. It is still quite warm and very sunny, so I still have to be careful. I do find that the orchids outside look very happy to be there. I'll probably wait a bit longer before I put more out there because there just isn't enough room in the shade for all of them!

Last year I left them out there until the overnight temperatures dropped to about 60.

The main thing is to start them off shady and move the higher light ones into brighter settings gradually. Too much sun too soon will set them way back.

I cannot speak to cattleyas or epidendrums, but I do have quite a few phalaenopsis, and all of them absolutely thrive outdoors! It's seriously the best thing I do for them.

However, as with all orchid advice, it's important to be aware of your own growing conditions. I'm in northeast Oklahoma, and it's really humid and breezy during our spring, summer and fall. It might not be quite as orchid-friendly where you are.

I let mine stay outdoors as long as possible. They grow vigorously (green growth, like leaves and roots) between temps of upper 60's and mid 80's (F). However, they're also fine outdoors when the night drops to the low 50's, or the day climbs to the high 90's. If you subject your plants to extremes like I do, it's important that they have at least a 15 degree temperature difference between day and night so that they can recover. If they're subjected to a constant 98 degrees for several days on end, they'll stop growing and start to look pretty pathetic! (I know from experience, sadly.)

An extended temperature drop will go a long way towards produce a spike. Keeping the plant in the low 60's-70's while the spike matures may even ensure it produces the maximum number of flowers. (If anyone is interested in reading more about this, here's a cool article: http://ecaaser3.ecaa.ntu.edu.tw/weif...-flowering.pdf)

If you do decide to move them outside, put them in a very shady spot for at least two weeks. Remember, even the shaded areas outdoors are much brighter than it is indoors! The light intensity could burn them if you're not careful. You also may need to water them more frequently, as the heat and the breezes dry plants out pretty quickly. Finally, be vigilant to look for pests. Snails and slugs, especially, seem to have "orchid radar", so look out for their sinister slime trails.

Keep a close eye on your plants during that transition period, checking them multiple times a day to see if they are taking to it well, or are struggling. And let us know how it goes!

As it is still in the high 90s to 70s at night, I will wait awhile. I have an inset back patio area that will be perfect and can keep my tilted umbrella there for shade. It is generally pretty humid here. Are there any kinds of orchids that would not thrive outside in these temps?

Arrrrggghhhh.

Why is it Americans use Farenheit? Every time someone gives a temp, I have to do a sum and see what it is in real figures!

Yeah, we are down to the 20s some nights. When it gets a bit too cold I shall have to shift the phals to winter storage. I have welded up a shelf under the bench to take them all and keep the direct sun off them.

@bil
I saved this picture on my phone where I can find it very quickly.
I use it very often while browsing through OB
http://i.imgur.com/KgBqW7Q.jpg

That certainly makes conversions easier than trying to figure out why Europeans hold their cigarettes that funny way!:biggrin:

Ha! I do the same for Celsius figures! God bless Google conversions ;)

Now, why don't you Europeans invent a metric system for keeping track of time in neat decimal values? I could use that system!

Ha I just took mine in last night. It is getting too cold at night now. I left most of mine outside all summer long rain or shine. I did have to shade a few. Temp never got over 85. I live in the high sierra mountains. The nights would drop in to the 40s often but not for too long. My orchids seemed to love it Because I have 3 plants that are in spike now. I find my orchids like a 10 degree change in temp. As long as your nights don't get under 45F you should be fine leaving them out.

I think it all depends on what kind of orchids you have. I just had to water them a lot more when it was hot out. Make sure you keep a close eye on them.

Ah-hem... Now that I got that out of my system, I'll try to help you with your question, Trish!

Orchids do tend to fall into categories as far as preferring warmer or cooler temperatures. You can probably find out if your type of orchid is a warm, intermediate or cool-grower by looking up care sheets. You can start by looking here: https://www.aos.org/Default.aspx?id=217

Here's another chart that shows a few common species of orchids and what temps they prefer to grow (in both F and in C ;) ):About Orchids: Basic Orchid Care for Beginners - Temperature

Thanks for posting that. I use a slight shorthand. Instead of the precise method, (F minus 32 divide by 1.8 = C) I use F minus 30 and divide by two. It's a bit sloppy, but it works quite well.

Thanks for that shorthand bil. Easy to remember and precise enough for growing orchids

Here's a another article

http://staugorchidsociety.org/PDF/Alert-ColdWeather.pdf

You'll want to do a heat tolerance check of your species, but for the most part they can all go outside all summer long. I'm Austin where its much drier (heat plus humidity is better for the plants than heat and dry air) and I throw most of my orchids outside for the whole summer.

:rofl: I have seen some funny smokers over the years!

Seriously, you leave your orchids out most of the summer? In East Texas, we have high 90s and even 100s occasionally. Yes, the humidity would definitely be advantageous here. In such high temps, phals are okay even in the shade?

It's in the 90s and yes, even the 100s here in Tucson, too...and unless it's raining, we don't have the humidity you do, but my orchids (the ones I put out) enjoy it. I have to keep them in the shade and watered (unless the rain does that for me) and I will leave them there until nighttime temps drop to about 60.
If I had a safe place to put the rest of them out, I probably would. I have a very limited amount of bright shade that is also fairly critter-free. Last year I burned a few leaves when I miscalculated the change in the relative position of the sun as we got into Fall. I don't want to do that again!

The Phals might be a bit problematic, but with the higher humidity you might be able to get away with it. I'd use an "experimental" phal that you don't mind losing to try once before you throw them all outside. The other plants should do just fine.

Nana Trish, it sounds like you have mostly warm-growing types, so you should be able keep them outdoors from spring though fall. The precautions recommended by earlier posters regarding gradual adjustment to stronger light should be followed.

For this season you can still move plants outdoors to a location with filtered light and they should benefit. You can bring them back indoors when night temperatures will drop lower than the mid 40s F.