Light Requirements & Shade Cloth

[HiOrcDen]

Originally Posted by estación seca

Unless you're right on the coast in southern California, or it's always breezy, very few orchids will tolerate your unscreened sun in summer. Breeze carries off the heat formed by sun striking the leaves, and they remain near air temperature. But when the air is still leaves quickly burn in the sun.

The larger Angraecums are from the narrow eastern wet strip of Madagascar. The land rises rapidly from the sea west to the spine of mountains running the length of the island. There is almost always an onshore breeze cooling the plants growing up in trees.

I have somewhat similar conditions. I am on a hill (not a quite a mountain haha) a bit more than a third of a mile from the ocean. There is a constant breeze during daytime, except on the few very hot summer days. Night time tends to be very still, except high winds a few days a year.

Thank you for this information, especially the dynamics of the sea breeze, a lot to consider. So you said not many orchids would enjoy full sun. Would you give examples? Or perhaps I could google it

[Roberta]

The orchids that I grow the brightest are Cymbidiums, and Laelia anceps and its relatives (L. autumnalis, L. gouldiana for example) and their hybrids. When I first moved to my house, I didn't provide any shading at all, the Cyms especially got really yellow but still did fine. But they still bloom well and look better with 40% shade over them.

Also a consideration with new plants that WEREN'T grown outside in California... typically they have experienced less light, so increase gradually. If light is really inadequate, the worst that happens is that they don't bloom. But if it seriously too much (such that leaves get hot) they can burn almost instantly. So it is better to err on the low side, increase light gradually. Feel the leaves during the brightest part of the day - if very warm to the touch, back off the light a bit.

[estación seca]

In your situation - reed stem Epidendrums grow like weeds in garden beds and flower all year; Cymbidiums; larger species of Eulophia like macra and petersii; the big red Renantheras and hybrids, though they won't like cool, wet winters; Papilionanthe/Vanda teres and hybrids, though again they don't like cool wet winters; Brassavola nodosa and most primary hybrids with it; Cattleya/Laelia purpurata and many of its primary hybrids; most Mexican Laelia species like anceps, autumnalis, gouldiana ; many Australian Dendrobiums like Den. speciosum; many of the larger Sobralias; Cyrtopodium, though most need a dry winter dormancy.

There are a number of Oncidium species formerly called Odontoglossum that like high light yet cool temperatures. The genus Cyrtochilum also grows like this. Living where you do I would be tempted to try them. Not many people can grow them well due to too much heat. Talk to an expert like Andy at Andy's Orchids before trying these. The South American vendors sell them.

And quite a few of the larger Phragmipedium species grow in full sun at higher altitudes with their feet wet.

[Roberta]

I do grow Renanthera imschootiana outside, it doesn't seem to mind the cold. Most of the Vanda group tends to want more warmth than our winters provide but there are some delightful exceptions.

When Andy is having Open House (there's one next weekend, probably another in June-ish) it's great to wander around the nursery and see where he grows things, When I go, I focus on the unheated shadehouses - the temperature range in Encinitas isn't that different from where I live. Sometimes the tags reflect that and sometimes they don't ... one can learn a lot by observing. And the bonus is, the plants are already acclimated.

(Being close enough to visit the nursery is fantastic for one's orchid growing. Deadly for the bank account, but IOM-It's Only Money... )

[HiOrcDen]

Originally Posted by estación seca

Unless you're right on the coast in southern California, or it's always breezy, very few orchids will tolerate your unscreened sun in summer. Breeze carries off the heat formed by sun striking the leaves, and they remain near air temperature. But when the air is still leaves quickly burn in the sun.

The larger Angraecums are from the narrow eastern wet strip of Madagascar. The land rises rapidly from the sea west to the spine of mountains running the length of the island. There is almost always an onshore breeze cooling the plants growing up in trees.

That is all so good to know, thank you! I have a somewhat similar climate. We are a little more than a third of a mile away from the ocean, on not quite yet a mountain lol just a hill about 672'. When cool to warm it is always breezy. Again thanks for the info about the habitat, valuable to work with!

[estación seca]

Oh, and many species of what used to be called Schomburgkia, now Myrmecophila. And the similar Laelia, now Myrmecophila superbiens.

[Roberta]

Another little observation... In the Cattleya tribe, L. anceps and its close relatives have their leaves pretty much vertical. So they present the edges to the sun. Most of the others have leaves more horizontal - so they can look hard and tough, but are much more susceptible to sunburn, with much more surface area to hit. (Learned the hard way...)

[HiOrcDen]

Clearly so much to learn about Orchids to learn! So I am wondering about this... my Angraecum is pretty big, about 2 feet with no spikes. It was kept all day yesterday outside. I used 30% shade cloth, doubled over towards the brightest sun of the day.

There were a couple of what looked like singes at the outside edge of the plant, which may have barely received full sun on the edges, outside what the cloth covered. Or could those singes in a small spot have been from the entire plant receiving two much sun? And I suspect the bit of wilting and darkening comes from bringing inside, being overly cautious?

Basically asking if my setup is okay, 60% towards the hottest sun, 30% during the day. if I make sure the plant is completely behind the shade cloth lol . Also wondering, would someone throw up a number for safe minimum night temps for this category?

[Roberta]

I find 30% shadecloth to be not very useful, very small difference from nothing, but if you double it, good shade. This is very much a learning process... your yard is different than mine. Orchids do things very slowly. An Angraecum Crestwood at 2 feet is still a young plant. My related one (A. sesquipedale) blooms in December/January. So end of the year is a good possibility. Can't do categories for most genera, need to get down to the species level to be accurate. But for Angraecum Crestwood, the plant will be fine down to 40 deg F, even lower for short periods. This time of year, fine outside. Next winter, especially if you see signs of spikes, bring it in when nights get down to 45 deg F or so. I have found that when a plant will tolerate outdoor temperatures, it usually does better outside than inside or even in the greenhouse - better light, better air movement, and usually better humidity. If you put it out now (nights are mostly above 50 deg F ) it will acclimate, and then will be fine as the temps dip in the fall. And I would keep it under shadecloth... Especially since you just got it, if it is moved to more light it needs to be gradual - and with spring and summer coming, some protection is in order anyway.

In general, you can push the temperature range considerably (especially to the low side) if the plant has a chance to acclimate. My outdoor plants (about 90% of my collection) have seen occasional frost with no damage. It's never more than a few hours, and there is warming during the day, that's how one gets away with it.

[HiOrcDen]

Originally Posted by Roberta

I find 30% shadecloth to be not very useful, very small difference from nothing, but if you double it, good shade. This is very much a learning process... your yard is different than mine. Orchids do things very slowly. An Angraecum Crestwood at 2 feet is still a young plant. My related one (A. sesquipedale) blooms in December/January. So end of the year is a good possibility. Can't do categories for most genera, need to get down to the species level to be accurate. But for Angraecum Crestwood, the plant will be fine down to 40 deg F, even lower for short periods. This time of year, fine outside. Next winter, especially if you see signs of spikes, bring it in when nights get down to 45 deg F or so. I have found that when a plant will tolerate outdoor temperatures, it usually does better outside than inside or even in the greenhouse - better light, better air movement, and usually better humidity. If you put it out now (nights are mostly above 50 deg F ) it will acclimate, and then will be fine as the temps dip in the fall. And I would keep it under shadecloth... Especially since you just got it, if it is moved to more light it needs to be gradual - and with spring and summer coming, some protection is in order anyway.

In general, you can push the temperature range considerably (especially to the low side) if the plant has a chance to acclimate. My outdoor plants (about 90% of my collection) have seen occasional frost with no damage. It's never more than a few hours, and there is warming during the day, that's how one gets away with it.

I appreciate the concept of acclimation! So I should observe my plants, and see how they respond to weather. Thank you for this.

So I am really curious about this. As I said I had 60% towards the brightest sun of day, and 30% cloth just towards the last couple hours of sun. All the plants seemed okay.

The Angraecum had a couple singes only on the edge of two lower leaves on one side. Could this be the result of the whole plant receiving too much sun? Or is it my theory that the sun peeked around the shade cloth, on a tiny uncovered spot lol. I tend to think this, since there was no other damage on this plant and none on any others... Thank you again! Though I feel like I am asking too many questions!

---------- Post added 03-13-2022 at 12:01 AM ---------- Previous post was 03-12-2022 at 11:28 PM ----------

Oh, an addendum... I was just looking at my setup, and it looks like it's getting bright direct sun, through 30% in early-mid afternoon. If the plants are not showing signs of distress after one day, does that suggest their conditions are good? For the moment I'll place all behind 60% at least