The new grow room

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So we moved into the house in Cornwall in March this year after five months on the coast in Wales. The Catts now have their own dedicated small box room with three Vipara LED lights.
These are slung from clothes racks. The catts are on the floor. The lighting is on from about 8 am to 10pm. In the corner of the room is a floor fan with it pointing to the ceiling.
This results in the room temperatures being anything from 25-30c during the day, mostly from the heat from the lights. When the lights are switched off, I open the door to the room and switch off the fan, to allow the heat to dissipate and the trickle vents from the two windows to reduce the temperature to anything from 19 to 22c. IMG_1422.jpeg IMG_1423.jpeg IMG_1424.jpeg IMG_1426.jpeg
We are lucky that there are four solar panels on the roof which help run the LED’s.
So the temperatures are warm and there is a small dip at night which so far, appears to be enough. The fan provides air movement to circulate the heat from the LED’s.
I don’t have to worry about humidity in Cornwall. We are only a few metres from the sea. It’s more than enough year round.
 
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Another plus point of living here is that the tap water comes off the moors and has a low enough level of TDS to be able to be used directly on the plants. So the catts are watered and fed with this plus half rate rain mix year round. I don’t know what the final feed level is in micro Siemens.
I’ve never tested it.
The biggest job is to take all the catts out of the grow room once a week to water them. It’s a bit of a chore but it means I get to inspect them closely every week.
Almost all the plants are growing in a ‘pot in pot’ system. Many are growing in net pots to provide excellent drainage and air to the roots. This summer when the plants were in active growth, I’ve allowed the outer pot to retain a bit of moisture in the bottom after watering. The plants seem to seek this out and many having thriving roots outside the pot. See below.IMG_1427.jpeg IMG_1428.jpeg
I like this halfway house way of growing catts, between pots and mounted and so far, they seem to be thriving.
The plants are almost all in pure orchiata bark, with a bit of sphagnum on the surface if I think they need it. Just a few of the smallest divisions are in pure sphagnum. As orchiata is now unobtainable after Brexit, I’ll be looking for a substitute soon.
 
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Nice, David. When you were growing at your windows, I think your plants naturally got a winter rest with reduced light intensity and cooler conditions. I don’t know if you reduced watering and nutrition for winter or not. Are you planning on keeping 14 hour days, steady light intensity, and steady temperatures the whole year? Can you measure light intensity at the leaf mid-zone in your new setup or are you guesstimating how high to have the lights?
 
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I’m not sure yet about a winter regime. I’ll probably take the lights down to be about twelve hours. The day and night temperatures will naturally drop a bit. It may be enough. I don’t know. We’ll see.
I’ve never tested the light levels. I go by the effects on the growth of the plants and the colour of the leaves. The growth so far has been excellent and the new blooms are better than ever.
All the plants that I would have expected to bloom have done so, so far. The only ones that didn’t were the three warscewiczii clones.
The labiata and lueddemanniana plants are starting new growths.
The purpurata clones are looking amazing.
So all in all, I’m pleased with things.
 
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I’m not sure yet about a winter regime. I’ll probably take the lights down to be about twelve hours. The day and night temperatures will naturally drop a bit. It may be enough. I don’t know. We’ll see.
I’ve never tested the light levels. I go by the effects on the growth of the plants and the colour of the leaves. The growth so far has been excellent and the new blooms are better than ever.
All the plants that I would have expected to bloom have done so, so far. The only ones that didn’t were the three warscewiczii clones.
The labiata and lueddemanniana plants are starting new growths.
The purpurata clones are looking amazing.
So all in all, I’m pleased with things.
In the natural habitat, the day length for all the unifoliate, large-flowered Cattleyas is not less than about 11.5 hours or more than 12.5 hours. With LED lighting, which is constant, as compared to your windows where the light intensity is rising and falling during the day, you want an intensity that is about half the peak that you had at the windows but carry this intensity through the entire day. This gives the same daily light integral.

I have been on a deep dive into the winter rest of the unifoliate, large-flowered Cattleyas and I purchased the Baker culture sheets for these species. It is interesting and fun to try and customize the temperature, and particularly the fertigation, characteristics of the in situ species.

For some, the temperature drop in winter is of some importance. For others, it isn't the temperature change but the change in the rain frequency that triggers a growth. I think it is OK if I copy a small section from the warscewiczii document here.

"One grower reports that temperatures must be less than 62F (17C) when new growths are 1/4-3/4 in. (0.6-1.8 cm) long for bud formation to be induced. It may eventually be found that dry periods initiate new growths, cool
temperatures initiate flowering, and that plants can flower twice a year
if these conditions are met. This is our speculation, it has not yet been determined.
Research with cultivated plants indicated that flower buds of Cattleya warscewiczii were initiated in late winter as days become longer and night temperatures drop to 55F (13C). Flower buds did not form if plants were
temperatures drop to 55F (13C). Flower buds did not form if plants were grown with continuously long 16 hour days or at continuously warm night temperatures of 65F (18C)."
 
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Thanks for this information Terry.
Both warscewiczii and it’s hybrid x hardyana are the only species that haven’t bloomed when I’ve expected them to.
The following species all have bloomed this summer after producing a growth in these new conditions: gaskelliana, labiata, percivalliana, trianae, lueddemanniana.
So it will be interesting to see how things develop over the next year or so.
 
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Thanks for this information Terry.
Both warscewiczii and it’s hybrid x hardyana are the only species that haven’t bloomed when I’ve expected them to.
The following species all have bloomed this summer after producing a growth in these new conditions: gaskelliana, labiata, percivalliana, trianae, lueddemanniana.
So it will be interesting to see how things develop over the next year or so.
That’s why it is a great experiment. Orchids, as extremophiles as some have called them, are also adaptable. Knowing the range of conditions in which various species will grow and flower is important. Maybe some cultural items help a species bloom optimally but if these items are not easily accomplished in a growing space and the species still grows and blooms adequately, I would still attempt to grow it. Some of the things I am doing to match in situ conditions of various species are fussy and I might not need to do them.
 
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I’m not sure yet about a winter regime. I’ll probably take the lights down to be about twelve hours. The day and night temperatures will naturally drop a bit. It may be enough. I don’t know. We’ll see.
I’ve never tested the light levels. I go by the effects on the growth of the plants and the colour of the leaves. The growth so far has been excellent and the new blooms are better than ever.
All the plants that I would have expected to bloom have done so, so far. The only ones that didn’t were the three warscewiczii clones.
The labiata and lueddemanniana plants are starting new growths.
The purpurata clones are looking amazing.
So all in all, I’m pleased with things.
May want to drop to 11.5 hours darkness for a couple of months. I was instructed by Jerry Fischer years ago, most catts must drop below 12 hrs to bloom.
 
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May want to drop to 11.5 hours darkness for a couple of months. I was instructed by Jerry Fischer years ago, most catts must drop below 12 hrs to bloom.
The northern latitude greenhouse grower has day lengths that vary from 14+ in peak summer to 9- in winter, radically different from the natural habitat where day length varits from only 12.5 to 11.5. Even near the equator, where all the unifoliate large flowered Cattleyas grow, there is a modest change in light intensity from summer to winter as the sun moves and the greenhouse grower experiences this excessively. Most Cattleya species may not be very sensitive to this modest day length and light intensity change, but a few (notoriously labiata) are said to be. Kelly McCracken, in her Orchids series on LED lighting, stated that her commercial orchid grow houses use 12 hours throughout the year and she probably doesn’t vary the light intensity. She didn’t say if she grew labiata or the few other species that might be day length/light intensity sensitive.

Many Cattleya species are noted to initiate growth or flowering in response to changes in temperature or rainfall. The temperature change happens naturally in northern latitude greenhouses but it can be harder to reproduce in an indoor plant room. Rain in the natural habitat carries nutrients in the runoff so low rain may mostly cause reduced fertilization because many species (not all) continue to receive heavy dew and fog to provide moisture (without fertilizer) even when rain is very low.

I am trying to reproduce the in situ light, temperature, moisture, and nutrition changes for the species that I grow (a complicated challenge). However, I suspect that all of the fiddling isn’t necessary for most of the species. David is keeping conditions pretty steady through the year and will find out if any species don’t respond as well for growth or flowering. Deborah varies some things but not ridiculously like I am. All a good experiment. We need to observe carefully and report our results.
 
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Thanks Terry. I’ll probably put the grow room on a timer and drop the lighting to 12 hours during winter. The temperatures will drop slightly but not by much. I won’t be doing much more than that and we will see what adapts and what doesn’t.
 
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Kate, it is! I have to be very careful. Once a week I take every pot out of the room and water it individually. I water the net pot and leave it to stand in the water for a couple of minutes as it’s in a bigger pot. It gives me an opportunity to check each plants for issues and things like scale.
 
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William, the only plants I cannot get into net pots are the largest ones. But it definitely works wonders for root growth and general health.
Eric, it’s because I want to keep a pristine floor!
Also you have to pour the excess water off from the outer pots if you don’t want soggy roots. Tough to do if you cannot reach the pots!
 

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