All green but no bloom - how to bloom cattleya orchids

[Velamen]

Dear Experts,

How do I get my cattleyas to bloom? I realize you can't wave a magic wand and voila you got blooms! But my hunch is that I don't have the correct conditions to give the plants a chance to bloom as they should. The three pics below should show you healthy plants. To my untrained but hopeful eye there is no evidence of "bloom-readiness."

Here are the specs. for their artificial, indoor environment:

• Under 5000+ lumens of red and blue T5 bulbs. The distance between the hanging light tray and the plants is no less than 8 inches up to 1.5 feet at most.
• The light is one a timer for eleven hours of light.
• Please note, that the hanging light you see in one of the pictures is off. The hanging light I use is not in any of the pictures.
• I water them sparingly, when their medium and roots are so dry you can hear a slight crunchy sound when I gently lift the pots.
• I soak them in rain water for twenty minutes up to a half hour.
• I have ceased using my fertilizer (one high power with Superthrive and seaweed but read this can mess up blooms).
• I last used this fertilizer approximately three months ago and only sparingly.
• I have a separate fertilizer for blooms but don't use it as I assume that I would do so sparingly once there is evidence of blooming (is this wise?)
• I live in the northern latitudes, 39 parallel. With central heating and a slightly drafty room the temperature now in the daytime is above 75 degrees. At night, down to low 70s.

Given these facts and the photos below, am I on the way to let them bloom or is there something wrong with my configuration?

A little more history will help. I had to re-pot all three cattlyeas because of root rot when I had over-watered. Lesson learned! This was back in early spring, at least 7 months ago. I assume I have thrown off their blooming cycle by the fairly recent re-potting?

You will see that one of the plants has a lot of small green growth. When re-potting last spring I should have separated them and re-pot the other half in a different pot to give the plant some breathing room. New growth is already making an appearance in this crowed plant.

My question about this plant is, should I divide and repot or leave as is for now?

Thanks so much in advance for all your counsel. It's deeply appreciated.

Best,

Don "Velamen"

[ORCHIDJOE]

I would love to help you but I have no experience growing under lights, however I would say that your plants look very dehydrated, do you maintain a good humidity in your growing area. It might be a good idea, as you have cut down on the watering, to mist your plants at least once a day in the morning. I am sure there are more experienced growers to assist you, good luck,
Joe

[raybark]

The color of the leaves looks OK, so I really don't think lack of light is a major factor.

I agree with Joe about them appearing to be underwatered, and the root tips suggest the %RH is low, but I think you might be underfeeding, too. My recommendation is to divide 4 by the %N on the label, and absolutely soak the potting medium with that solution every time you water.

I wouldn't worry about the hormones, as it takes REALLY high doses - a tablespoon per gallon used very frequently - for flower deformation, and I have only heard of that in phalaenopsis.

[Velamen]

Thanks Joe and Ray!

Ray, do you mean PH value or RH (relative humidity). I do have a Better-Grow fertilizer with nitrogen and no urea. The amount of nitrogen in the mixture is 20%, so that means I use 5% to soak the plant with in water? I think you mean use one quarter of the recommend dosage. Right?

Thanks again.

Don

[Jx3]

I tried cattleya orchid hybrids under 6 4ft tubes for about 3 years and couldnt get them to bloom, massive roots and 10-15 growths per plant, good leaf color, etc. I put them outside this summer in almost full sun and left them until about a month ago when it started getting in the 40's at night. A few days ago i see two growths have early budding sheaths. I think the extra light and temp differences got them to produce. I can get everything to bloom under light except cattleya orchids.