Mrainey,
The watering should only be done when they have dried back. This will depend on what soil mix you have them planted in. If they lose their leaves and go dormant, then water very sparingly through out the winter months.
Lower light conditions may induce dormancy, but not always.
I check mine weekly in winter for water needs and usually fell their caudex.
If I ever find that the caudex starts to feel somewhat like a old carrot or potato, pliably soft (not mushy) then I know that I have left too long before watering. I always like to ayr on the side of caution and keep dry.

You will find that you need to treat each individually and not assume they all need water at the same time.

Hope some of this helps,
Rick

Rick is soooo right, Mrainey. He gave me the same advise the first time I got these plants and it really does work that way. Individual plants behave differently.

When watering, a sip translates to about a quarter of a cup, maybe even less. You'll know when the plants need a sip when the trunk is a bit wrinkled.

Just to add, your light should be on 14 hours during the day and off at night.

Pagan

Thanks... Why turn them off at night and leave on 14 Hours during the day?

Your fluorescent lights are supplemental to daylight. So they have to be off at night because plants follow circadian rhythms too. They need to do stuff at night that they don't do during the day.

Here is a link that might be useful: cycles

I use two banks of red&blue LED's and kept mine on 24/7 last year.

The stems grew so long that they were unable to hold the weight of the (many) leaves. All of the larger stems grew ~18-24 inches in four months. The leaves also changed their shape to a much larger leaf, and more rounded. The leaves did not revert back to the smaller size under regular sunlight this summer.

I allowed mine to grow like that all summer outside, and they probably only added another 2-4" of stem.

I just removed all of the growth from last year to make the plant look 'right' again.

Two banks of Red and blue LED? Can you send a picture do what your lights look like. Mine are above should they be different

I am definitely not a pro at indoor growing. Last year was my first year to place my plants under these lights. My adeniums have never been dormant. They grew all winter - too much actually! Of course, within a month of setting them up, I started leaving the lights on 24/7, so that may be why they grew so much. The lights triggered my plants leaves to turn the deepest green imaginable. The leaves also got much larger, and more rounded. I think the plants loved the lights, perhaps the leggy growth was because I simply left them on too long every day. I have now reset my timer to ~16 hours each day.

Each 'bank' is 12"X12" in a fixed enclosure. Total LED's in each unit = 112. I didn't count the red/blues exactly, but the way they are spaced, it looks like there are twice as many reds as blues. These particular lights are used by professional indoor growers and I got lucky enough to come across a used pair of them for a decent price on eBay. I added two of the new regular bulb shaped white LED bulbs this year as well.

A picture with the light on.

Wow. Can't do that. Hope my floursant lights do the job