Max light levels. Cats, dens, cymb, oncidium and vandas

[bil]

This is a question re the max safe light levels for these orchids. For example, the sun here is pretty bright and hot here in southern Spain, so these are all outside under a willow screen that must knock out 50% of the light.

Well, the usual happened, and an oncidium on the edge got moved a little, and I suddenly realised that this had been sitting in the full glare of the sun for a week. Point is, it looks better now than it has since I bought it.

So for these orchids (Cats, dens, cymb, oncidium and vandas) How much is too much? I don't want to find that they haven't been getting enough light, because every one keeps emphasising how important it is that they get enough light, and equally I don't want a collection of crispy critters. I have a couple of Phals with sunburn trying to get them the best position.

[MattWoelfsen]

The light I provide my orchids--not scientific--you will get some very specific information from others, I am sure. So my reply will bump your query.

I started growing Phalaenopsis. Phalaenopsis can be grown in full sun as the sun rises in the east. That is where I have my Phals, not a single burn amongst my Phal tribe. I grow Phals, Papiopedelium, and Pleurothallis in the same eastern facing light. Neofinetia falcata is my largest group of plants, and I have them growing in eastern light as well. Another description is "bright shade".

Next up from this group is Dendrobium and Oncidium. There are several different kinds of Dendrobium that I raise--some like it very bright sun but in-direct sun.

Cattleya, especially Laelia rupicolous orcids (from Brasil) like even brighter light and some tolerate direct sunlight--although you have to harden them before placing them in bright light. Cattleya are very responsive to light--they'll get very red leaves.

You described your light source as "under a willow screen that must knock out 50% of light". This is pretty bright so I would guess, most of your plants will thrive in this light. Phalaenopsis probably need a little less light. The challenge of growing outside is the fact that the earth moves or the willow screen might be blown askew by the wind?

[bil]

Originally Posted by MattWoelfsen

The light I provide my orchids--not scientific--you will get some very specific information from others, I am sure. So my reply will bump your query.

I started growing Phalaenopsis. Phalaenopsis can be grown in full sun as the sun rises in the east. That is where I have my Phals, not a single burn amongst my Phal tribe. I grow Phals, Papiopedelium, and Pleurothallis in the same eastern facing light. Neofinetia falcata is my largest group of plants, and I have them growing in eastern light as well. Another description is "bright shade".

Next up from this group is Dendrobium and Oncidium. There are several different kinds of Dendrobium that I raise--some like it very bright sun but in-direct sun.

Cattleya, especially Laelia rupicolous orcids (from Brasil) like even brighter light and some tolerate direct sunlight--although you have to harden them before placing them in bright light. Cattleya are very responsive to light--they'll get very red leaves.

You described your light source as "under a willow screen that must knock out 50% of light". This is pretty bright so I would guess, most of your plants will thrive in this light. Phalaenopsis probably need a little less light. The challenge of growing outside is the fact that the earth moves or the willow screen might be blown askew by the wind?

Thanks Matt

Part of the problem for a noob is the widely ranging advice we see. The scale of intensity I found had the high range of light at 3-4K foot candles, and the sunlight here is 10K easily. Oncidiums are rated at less than 3K, so goodness only knows why it hasn't cooked and turned brown!

Under that willow screen, the Cats look quite dark green. There is no danger of it blowing away (a good point to bear in mind. Such screens need to be securely fixed.) Before that happens the plants themselves will be well on their way to the Land of Oz.

[AnonYMouse]

Andy's Orchids has guidelines for the species he carries.

Internet Orchid Species Photo Encyclopedia also has guidelines.

For hybrids, you can google cultural info or guess based on their parentage.

Good luck!

Edit to add: As Matt mentions, outdoors light is always moving. Even fully exposed, the intensity changes over the course of the day.

[My Green Pets]

I have to say that this is an ongoing experiment that should be part of the enjoyment of the orchid hobby.

A story: one September afternoon, I left my two Phals and an Oncidium right next to the open window and forgot about them. They received direct sunlight for 2-3 hours. Guess what? No problem. They showed no evidence of burn.

Now, if I had made the same mistake in June, it well could have been a different story.

In southern spain, the sun is going to be intense at noon in summer, and very bright but less intense in winter. your catts, vandas, and oncidiums might be able to handle full sun all day in those cool months. In the summer, that could be a recipe for fried orchid.

As matt said, direct light from 8-10 AM is not the same as direct light from 12-2 PM.

The plants will tell you how much is too much. Touch their leaves. Are they cool? Warm? Hot? Anything warmer than 'a little bit warm' is too much. If the leaf feels very warm or a little bit hot, it is frying.

Phals, with their big, fat, juicy leaves, heat up quickly in strong light. All that moisture inside them bubbles up and destroys the surrounding tissue. Thin oncidium leaves and rigid, sturdy cattleya leaves can handle that heat more effectively, but they, too, have their limits.

That's all I can recommend. Go forth and touch your orchids. Hot leaves are a big no-no.

Also, I love Spain. Are you near the costa del sol? Malaga I remember was humid, perfect for orchids. However the arid, inland mediterranean climate of say, sevilla, will dry them out. Those things will have a strong influence on your culture.

[bil]

Originally Posted by CambriaWhat

I have to say that this is an ongoing experiment that should be part of the enjoyment of the orchid hobby.

A story: one September afternoon, I left my two Phals and an Oncidium right next to the open window and forgot about them. They received direct sunlight for 2-3 hours. Guess what? No problem. They showed no evidence of burn.

Now, if I had made the same mistake in June, it well could have been a different story.

In southern spain, the sun is going to be intense at noon in summer, and very bright but less intense in winter. your catts, vandas, and oncidiums might be able to handle full sun all day in those cool months. In the summer, that could be a recipe for fried orchid.

As matt said, direct light from 8-10 AM is not the same as direct light from 12-2 PM.

The plants will tell you how much is too much. Touch their leaves. Are they cool? Warm? Hot? Anything warmer than 'a little bit warm' is too much. If the leaf feels very warm or a little bit hot, it is frying.

Phals, with their big, fat, juicy leaves, heat up quickly in strong light. All that moisture inside them bubbles up and destroys the surrounding tissue. Thin oncidium leaves and rigid, sturdy cattleya leaves can handle that heat more effectively, but they, too, have their limits.

That's all I can recommend. Go forth and touch your orchids. Hot leaves are a big no-no.

Also, I love Spain. Are you near the costa del sol? Malaga I remember was humid, perfect for orchids. However the arid, inland mediterranean climate of say, sevilla, will dry them out. Those things will have a strong influence on your culture.

Thanks for a thoughtful, informative reply. We are on the South atlantic side, well away from Malaga. Hot and quite drying.

As you say, it's an ongoing experiment.

[MattWoelfsen]

Ongoing experiment? So true. As we all know light is one aspect of growing orchids. I have observed this of my Laelia--while they enjoy a lot of light, they cannot survive without a lot of moisture. So early in the day I give them a lot of water. Throughout the day of light, they are drying out. By evening they are almost dry. During the night they get a little more moisture from dew.

Light plus moisture is part of the experiment. For me a third factor is air. I can give plenty of light and moisture to my orchids but they need moving, fresh air to thrive. I think this is why my orchids do so well outside. In the winter time, I try my best to duplicate these same conditions but in that season, you have to consider cold temperatures and how to manage the orchids cultural requirements. Yikes! I just made this growing business more complicated.

[bil]

I am reminded of the Monty Python Inquisition sketch.

Our main weapon is the correct amount of light.

And water!

Ok. Our main weapons are the correct amount of light and water.

And air!

Ok. Our main weapons are the correct amount of light, air and water.

And potting medium!

Ok. Our main weapons are the correct amount of light, air, potting medium and water.

And fertiliser!

Arrrrggghhhhhhh!!!

[Fairorchids]

If you raise the light level gradually, many orchids can be grown in higher light than we normally give them.

I am in NJ at 40 deg N, which is roughly same lattitude as southern Spain. Here I can bring orchids outside at the end of May (Cymbidiums in early May).

Cymbidium: I place these on north side of the house for 7-10 days = in shade from 10AM to 6PM (10-18). Then they can go into full sun, but you need to water more in the high light.

Vanda, incl Neofinetia, Renanthera & Rhynchostylis, I place under a lattice (I will post photo later) for 7-10 days. Then the lattice comes off and they get full sun through the end of September. I try to spray them with water twice a day, while in full sun.

Cattleya, Zygopetalum, Oncidium hybrids & most Dendrobiums do well in mottled light, standing under the hanging Vandaceous plants.

This year I am growing all my reedstem Epidendrums & Aussie Dendrobiums (kingianum, speciosum & mixed hybrids) in full sun after 1 week under a lattice. I tried a Dendrobium Phalaenopsis hybrid also, but it could not handle the full sun, so it came back inside.

Paphs I always cover with a 40% shade cloth (conventional wisdom says 50% for Paphs).

And here is photo of my Vanda rack, with Catts etc. standing at the lower level. I start out covering top & 4 sides with lattice panels (1 handing on the right side), but they come off after 7-10 days. I do have to water more while the plants are in the full sun.

My guess is that Cattleyas can tolerate 'almost full sun', provided that light level is raised in 2 steps (from lattice shading, to about 15-20% shade).

[MattWoelfsen]

LOL Bil. That sums it up pretty good. BUT, there is always a but....potting media is not as critical as light, water, and air. For the most part orchids live in trees, tree branches, on rock outcrops, and other in hospitable places for regular plants. I think orchids were intended to colonize these places and lead the way towards taming their environment. There is nothing scientific about what I just stated. All the different types of orchids I have owned, I have tried to understand their native habitat. I figured if I knew their provenance, I could try to provide the same conditions and they would grow here in Fort Wayne, Indiana. Or over there in beautiful Spain.