What do you consider to be "heavy doses of artificial light"? Just curious.

Andy- I got my Roebellini (potted of course) to flower not this past summer, but the summer before. I think the key is full sun. 2 summers ago, I had it in front of a south facing wall, but this past summer I had it in front of an east facing wall, so it didn't get sun after about 12 noon. I water mine about every day in the summer and fertilize with miracle gro once a week, but like I said, it didn't flower this past year, so I think the key is full sun.

Xerophyte-
I have a grow light that is postitioned about a foot from the growth center of my oldest roebi. I turn it on in the morning (7:00ish) and off (6:30ish) when I get home from work. I never used to do that before and the weak winter growth would brown when I put it in full sun again in May. Now the growth center looks much thicker and healthier. It is in a giant pot that sits about 2 feet from a heat vent. It easily has soil temps in the 70s all winter. My newer one that had the seed pockets also gets artificial light all day although the light is further away because I have about 10 palms all bunched toghether in a spare bedrrom. It gets full afternoon sun from a 5X3 south facing window. I have never used artificial light this liberally before.
Islandbreeze-
I put my Roebis in full sun all summer long (10:00-8:00) in June-July. I can see a lot more growth on them this winter with all of the artificial light.

Sometime around mid summer in South Florida for established plants in the ground. Long days (getting shorter however), high temps and high humidity. Hope this helps.

Thank you Steve. I'm at the mercy of mother nature in the summer. Maybe by stimulating so much more growth this winter it will help. I can't leave mine out for the summer until mid-May on average (last chance for frost). That seems a long way off but it will be here before I know it. One of the biggest drags around here this time of year is overcast days going on and on. We may get one sunny day out of 10. Having said that overcast days keep it warmer which is nice for the gas bill.

andy

What type of lights do you use? I have a 175W metal halide spotlight over my big bottle palm to supplement the window light. For good growth of high-light requiring plants, you want min. 1000 foot-candles per sq ft, which is not easy to achieve with most lights.

I keep watering of my roebellenii minimal to discourage new growth, so I don't experience leaf burn when they get put out again in the summer.

Can't do that with Hyophorbe, they keep on growing, and if not watered, fertilizer salts build up and cause brown-tipped leaves. That's why I set up a metal halide spotlight, which adds 10,000+ lumens over about 9 sq ft of growing area, which works well to cover most of the upper leaves.

Eventually when it becomes a much larger plant, I will have no choice but to hang a substantial light source, such as a 600W HID lamp, during the indoor growing period (mid-October to early-May).

Honestly I'm not sure. I am work right now. I have two that I bought from a chain of nerseries in the area called "English Gardens". They are specifically designed for growing plants. They do a great job.

Mine flower in the summer and this year one plant made seed.