How do I acclimate orchids to full and direct sunlight without killing them?
 

Hey everyone!

I have recently obtained some high-light orchids (something I never said I would do, but- well- you know what happens when the orchid bug bites you!!). I have mostly phals, oncidiums, and paphs up until this point, but the new additions include:
1 NOID Den Nobile
1 NOID Mini Cattleya
1 Brassavola Nodosa x Grandiflora
1 Den Kingianum

I live in a climate that is cloudy all winter, and will have intermittent REALLY bright days all of a sudden. With this weather pattern, I really fear that the plants will get a sudden shock of sun, burn, and die a horrible and painful death, and I would cry and cry.

However, I know these guys don't like to bloom unless you give them lots of sun, and in summertime, we basically have nonstop cloudless skies and full sun is plentiful.

But between summer and winter, I am worried. Lately I am trying to keep them on a windowsill while I am home and able to frequently check if the leaves are too hot. I have a window that is very lightly screened, and when I leave home I place them adjacent to the window. At the moment, they are getting a nice breeze and full direct sunshine with the window open.

Should I treat this like tanning? Should I give them 30 minutes full sun for a week, then an hour for another couple weeks, and then 1.5 hours, and so on?

What do you do? I know that brassavolas get red when they are getting the sun they want, but I am scared of burning and killing them in the process!

Below are pictures of my 3 locations. 1 is with open window, 1 is closed, and 1 is the corner I move them to next to the window to give them bright but indirect sun.
PS My window faces SOUTH! :)

The simple answer is, GRADUALLY. I can't put mine in the full sun here in South Spain, it's just too hot.

Do you know what conditions they came from? If they are blooming now, they were exposed to ideal light.

This time of year, with those 4 plants, I'd stick them in a east facing window and let them be. (Bright shade for 6-8 hours).

All I've got is south!! I just feel like the brassavola and cattleya especially are going to want a lot of full sun.

---------- Post added at 04:34 PM ---------- Previous post was at 04:32 PM ----------

Haha, I am in a really temperate climate and it is really not very hot for most of the year. Usually we get like one week in summer that is 40°C, but the rest of summer stays closer to 30°C.

I think I can acclimate them to full sun, but I am just scared I will overdo it. Being a person who sunburns VERY easily, I know what it feels like to be cooked too long!

You could put up a sheer cloth or screen on that window to filter the sun slightly.

I'd say picture #2 fits the bill.

I usually wait for outside temps not to go lower than 50..before I bring them out to my growcamp. Temps rise fast here, but overnights at this time of the year still goes at the low 40's.

Your current set-up by the windowsill is just fine, so it gets used to the sun. But watch the outdoor overnight temps.

I have quite a few plants and every spring, they all go outside. Some of my plants go into full sun from being wintered over in a dim, north-facing window (jasmine, hibiscus, etc.). How do I do this? Gradually. I put them outside on my porch or in the doorway of the garage (with the door open) where they are in bright shade and over the next week, gradually move them into higher light. I have discovered that if the week is overcast, you have to take things slower or that first sunny day could burn some leaves (don't ask how I know this).
Plants/orchids that prefer shade will stay in bright shade. Their leaves are often thin or don't have protective pigments and burn easily.
Having grown for many, many years in south-facing windows, I don't think you will need to protect those orchids from the sun. The only problem you might have is on a hot day with direct sun for too many hours. Living as far north as you do, that is mostly a potential problem in the spring and early fall.

Since it is a south facing window, the sun may not be as direct during the summer.
I have large south windows that I use for my orchids in winter (lots of direct sun, never seems to bother them) but in summer they are mostly shaded.

I agree with Silken, hang a sheer curtain if you are worried about it.


Maureen

Of the plants you list the only one I keep is a D. kingianum. Once night time temps stay reliably above 45F or so it will be moved outside to the east side of my house. After a couple weeks there it will come out to the south side under an overhang which will prevent the noon time sun from directly hitting it. A couple weeks after that it will be moved out into full sun, from sunrise until about 3pm. Alongside will be a D. speciosum, a D. aggregatum, a D. loddigesii, and all my Catasetum hybrids. There is no way you are going to overlight those plants on that windowsill if you take a bit of time to acclimate them.