under lights is different than greenhouse
A couple points rather than a coherent response.
Compared to Maudiae types generally multiflorals want more light, coarser, more open potting mix, more air movement, temps above 60 F at night, more humitidy, and more time. Most want some extra calcium in their potting mix (oyster shell, limestone or horticultural pelletized lime)
I have succesfully bloomed Paph rothschildianum and philippinense under 4 tubes of plain old cool white fluorescent shop lights. The trick is you can make up for lower light intensitities by increasing day length. To do it I used 18 hours of light, 365 days of the year. Paphs are not at all day length sensitive for bud initiation. (some Catts and some Oncidium are day length sensitive) It is a waste of electricity to go with day length longer than 18 hours, at least according to a Weyerhauser study in pine trees.
I have successfully bloomed sanderianum under 430 watt HPS, and it actually was off to the side, not in the higher light area, so I think you could bloom a sanderianum under 40 watt shop lights. I grew under shop light only for over 15 years. Brighter lamps have their advantages, today I use 40 watt shop lights, 430 Sun-Agro HPS, 250 wattt MH and one 1000 watt HPS. Each area has benefits and draw backs. If I were to do it again, I would skip the 1000 Watt HPS as a waste of electricity.
Humidity - 50% is about all I shoot for, it is not ideal, but it seems to be high enough that if I keep good air movement, and don't dry them too hard between watering I get good enough growth. You have to be realistic in working the compromise between growing your plants and peeling the paint off the walls.
Frequently people state that this paph or that should flower every year. This mistatement is due to the fact that most of us are temperate climate growers and are used to annuals in the garden. If you follow the life cycle of a growth on a Paph, none of them bloom every year on an annual cycle. Typically it takes between 18 months and 5 years to mature a growth for most Paph species, single growth plants can take even longer. These are long lived tropicals. They do not need to follow a 12 month cycle. Paphs that bloom every year are multigrowth plants with growths in various stages of development. If you get your 2 or 3 growth Paph philippinense to bloom every other year you are doing quite fine. Once it is in a 12 inch pot with 15 or more growths it should start blooming every year. I have gotten old, fat, gray and cranky waiting for my Paph stonei and micranthums to bloom. One of my stonei seems to be on a 13 year cycle for each growht. Alright, I know somebody will post that they bloom some paph 8 months after they took it out of flask, but those are the very rare exception. Especially under home conditions, it takes years to mature a paph growth.
In the Memphis area your summer heat is a real problem for growing paphs outdoors, my friend in Greenville MS just south of you can not grow many Paphs because it does not cool off enough at night. Indoors you have the advantage of the air conditioning for your nightime temp drops. You should be able to do a fine job in Memphis. Good growing to you.
leo
