ok.. you got the info from the z8 and z9 peeps.. now lets talk reality in z5 MI ... the drop dead date frost free date [couple weeks sooner in suburbia].. usually.. for what that is worth.. in MI ... is 6/1 .. thats JUNE!!! for the rest of you ... and you still might get a frost/freeze ... coleus have no sense of humor about such .... you can start playing with extras around 5/1 .. outdoors.. if you put them in a wagon.. and pull them in and out of the garage.. at night.. should temps drop ... sooooo ... as to when to start seed.. count backwards from 6/1 .. include germination time.. and give them 4 to 6 weeks to grow .... so if it were me.. i would start new seed 6 to 8 weeks prior to 'go outside time' .... which means what.. march???? also.. note.. you dont have to plant the seeds all at once... try some 2/1 .. 3/1 .. and 4/1.. take notes .. and learn ... now.. your lights should be adjustable ... work that out if they arent ... give us pix of your setup.. we might have suggestions in a new post ... now.. these things are animals.. lol .. if you cut them back ... every 2 or 3 weeks.. and 'stick' them all .. you will be adding a wing to the house because.. being an exponential function .. 2 cutting.. will give you 4.. then 8.. then 64 ... etc ... [at every one of your cuts.. 2 buds min. will activate] what i used to do.. is.. root one or two.. of your cuttings.. throw the rest out in the compost pile ... at next pruning.. throw away one of the older plants.. prune the rest .. start two new ones.. etc ... basically.. cycle your plants.. young vigorous plants.. perform much better than old.. tortured plants ... and by 6/1 ... you want a bunch of young.. well rooted .. specimens.. not a bunch of old scraggly plants.. that will go into shock when you take them outdoors ... you want a young virile stud out there.. not grandpa ... you know what they are supposed to look like.. at point of sale ... and that is your goal .... i used to run my lights 16 hours per day.. with one on/off cycle in the middle of the off cycle.. it is said to confuse them into thinking the lights are on 24 hours ... and my lights were always about 2 inches from the tops of the plants ... and the light stand was in a closet ... and the lights ran at night ... so the heat from the lights ... kept them warm.. when my furnace kicked down to 64 at night.. in MI .... 64 degrees is not great seed germ. temp.. a 72 degree heat mat fixed that ... make any sense ... ken

The area that I am converting to my orchid nursery is about 10 x 10 feet. The walls are white and there is a double sliding door facing due East. There are no obstructions to block the natural light Can you afford an extra 384 KWh on your monthly electric bill? If so, then use two 400 watt Ceramic Metal Halide (CMW) bulbs mounted near the center of the ceiling. If the ceiling is painted white, don't use reflectors. It would probably be better to cover your sliding door with an aluminized mylar sheet. The only reason that I am recommending CMH over High Pressure Sodium (HPS) is that plants grown under HPS easily sunburn when moved outdoors. However, you can use HPS bulbs and then, two weeks before moving the plants outdoors, switch to retrofit Metal Halide bulbs to condition the plants so they won't sunburn outdoors. These bulbs require ballasts.

They look quite healthy- 2 100watt bulbs seems like a lot for Phaleonopsis because they're jungle plants mostly and would be living on trees probably below a canopy.

You need fluorescent lights. 48 inch shop lights are commonly used for these purposes. There are two kinds: One uses T5 bulbs and other T8. The T5 are fatter and use 48w per bulb. T8 s use 32w per bulb. I have two sets of T8 system. Each set costs about $20 (Fixture + bulbs). I can think that for an 8 ft x 8 ft area you will need 8 sets , if you use the whole area . BUT that sound like a commercial operation. Probably you can get by 4 sets maybe less. You will have to have a system that can be adjusted, as the seedlings grow. The easiest would be to adjust the lights. You will have to germinate your seeds first. For that, you do not need light but a warm place . Light is needed after germination. The distance between the top of seedling and the light should be no more than ONE inch. So there comes a need to adjust the lights very often as the seedlings grow. If I were you, I would start with 2 sets and do experimenting and you will then learn from your own experience and needs. There are wealth of information on youtube about starting from seeds on videos. It is much simpler that way to understand how to do it. There other other issues are involved beyond lighting, such as seed starting mix, watering, fertilizing, repotting.