Yes 400 Watt high pressure lights are good and can supply 2 m2 very well.
I presume that the following Lamps are the very best high pressure sodium discharge lamps:
400 Watts Plantastar (55000 Lumens, from Osram)
400 Watts SON-T-Agro (55000 Lumens; Philips)
both with E40 socket.

Hans-Werner

Hello Hans:

Thanks for the feedback and confirmation. I got my fixture today and MAN is it bright....but I think it'll do the trick for my babies...time will tell and I'll keep everyone posted on my progress.

I have maybe 20 species and F1 hybrids now and I use 2 400W MH (AgroSun)bulbs as the color of the light is much more pleasant (HPS looks like a sickly old horror movie to me) and I could care less about flower production...they flower outside in the summer when they are inclined to based on natural genetics and the color spectrum of MH is supposedly better for leaf and therefore bulb growth. Of course, I also have many other aroids under these lights and they flower from bare tubers and so lighting is not an issue.....you only want to increase tuber size to get to flowering size on these plants. Heat is also not an issue on any HID light if you keep a fan at low speed to get decent air circulation so this is not a problem.....in fact, I have to supply supplemental heat to the bottom of the pots since they are in my basement and they would be forced into dormancy at the 50-55F temps they see down there all winter. The only problem is the cost as we pay 10 cents per KWhr.....OUCH and I run the 800W for 16 hrs per day. It will be interesting to hear how yours do....I hope that they grow like mad for you :o) Dan

Hey Dan:

Thanks for letting me know. I had to choose between the MH and the HPS and chose the HPS based on the fact that it will help flowering etc and should still assist leaf growth. From what I understand MH DO provide better light but not as much lumens as HPS. They do have dual spectrum fixtures out there that can hold both HPS and MH in one however they ARE expensive. re: heat, I'm finding that it is not an issue at all. The top of the fixture is only warm to the touch. The ballast gets warmer than the fixture on top. I'll let you guys know how my hippi's do as they progress.

I asuume that the discussion above is for mature bulbs...right? What about amaryllis seedlings? What kind of lighting system can I use for my young seedlings (a few months old) to get them through this winter that can be efficient enough and economical. My older seedlings did alright last winter in a bright window. This year I would not have enough space. I am planning to grow them in my laundry room downstairs(60s temp.) that has this long countertop. I would highly appreciate any suggestions.

Hi Mariava:

I've been successful now in using 400W HID lights. You can use either Sodium Vapor or I believe the Metal Halide Lamps. They are more expensive that fluorescent setups but they do provide the footcandles necessary for proper growth. They would work very well for seedlings. If you do use fluorescent lights, make sure you have the seedlings no more than an inch from the lights to keep them nice and stocky. Of course, when the weather warms up in spring, you can get them outdoors in the full sun.

Good luck,

Gerard

Thanks for the input Gerard. Yes, that is what I am planning. Just grow them inside during the colder months and bring them outside in spring. That would be like 4 to 5 months at the most. I think I would try the cheaper (flourescent) lights first and do as you advice. I just want them to survive during those months. I have no problem on how they would look like and no time schedule to follow as to how big they should be when they are that old. They easily gain strength and grow vigorously during spring and summer anyway. How long should I run the flourescent lights anyway?

Hi Mariava:

Run the fluorescents for 12 to 14 hours a day. Longer is better than shorter duration wise. Remember to keep the lights as close as you can to the seedlings. Also, Don't worry about having special fluorescents for growing plants. You can get away with cool white bulbs which will be the cheapest and they'll keep the seedlings stocky.

Gerard.

Thanks for the tips Gerard. I'll be going to Knoxville TN tomorrow (nearest Home Depot and Lowes) and get me the stuff I need for this. Once I get it set up and working, I will be planting more seeds. I got to harvest some interesting crosses and would really like to get them planted. Have a happy Gardening Day!

Wow!!! I am bumping this up as I need better grow lights for my almost 1 1/2 - 2 year old seedlings. The flourescent lights did great with the less than 1 year olds. Now that they have grown bigger and taller, I think they need better and stronger lights.

I tried a search on ebay on "grow lights" and a LOT showed up. Any suggestions on which one to get? Or any other suggestions on where to get this grow lights?

How come I saw Sir Hans' set-up of his lighting for his seedlings and they looked like flourescent tubes?

Here is what ebay search results came up...

Here is a link that might be useful: Grow Lights on Ebay

Here is the thread where Sir Hans gave his advice on lighting indoors and a pic of his set-up. I kinda like his set-up. I think this would be great with the seedlings in a multi-level shelves of maybe in a grow cart.

What would be the US version of that "36 watt L-Floura (5-band spectrum) from Osram that Sir Hans uses?

Gezzzzz ...I have not heard from Sir Hans in a loooong time. I hope he is ok.

Here is a link that might be useful: Sir Hans' lighting set-up

Hi Mariava:

Thanks for writing. I looked at your search results and found a lot there. Or it seems like you found a lot. The HID lighting systems seemed VERY cheap and I'd be a tad suspect. But then that could be US pricing. I paid over $200 for mine which included the ballast and the bulb etc. Currently I'm using a crossover Metal Halide bulb for mine. Those LED lighting systems seem like the cats meow but I'm not sure how efficient they'd be for Amaryllis. Amaryllis need at LEAST 1000 foot candles to do half decently well. As seedlings, the fluorescent lights would be great but not as they mature. I'm finding that my 400 W setup is BARELY enough as my bulbs from last year didn't size up all that well although some of them will rebloom. They certainly aren't as big as others' bulbs on here who are able to have them outdoors etc. I'd hope that if you order from an ebayer at that cheap price that you don't get shafted. You should be able to get those HID grow lights at any hydroponics store but be prepared ... they might be expensive.

It appears that Hans is using fluorescent lights in his set up however I suspect that he shifts them out to better light when they reach a certain stage.

I hope that helps you out.'

Cheers,

Gerard.

Hi Cuddly!

Thanks for responding cause I really really need help in deciding which one to get. There are so many out there. I have been reading the Growing Under lights forum too and a lot of them recomend the T5 or T8 flourescent lights "for seedlings". I just don't know WHERE to buy them lights and fixtures. Definitely I will have to order this online as there are no hydroponic stores around here in my area.

I am currently "eyeing" on this one. Could you check it out for me? It says the whole fixture with 4 T5 lamps (46.5" long)will be 234 Watts and initial lumen would be 20,000. Would that be enough?

Here is a link that might be useful: Four 46.5

Hello Maria!

If that may be of some help to you, here is a picture of some seedlings of my crosses I started from seeds on July 17th, almost 4 months ago. They have alway been grown under a 4 tubes fixture, T4 (48") standard cool white fluorescent lights 15 hours a day. The dark gray 30cm-12" ruler gives you an idea of their size, they are 3 to a pot and what you dont see is that the diameter of the bulbs is almost the size of a quarter. I'm repotting them as of today, 1 plant per 7cm pot and I'll put them back under the same lights where they'll spend the rest of winter. {{gwi:431692}}De Divers

Laurier
My web site

Hi Mariava:

Those look like they should do the trick as they have a pretty good reflector. Being Fluorescent, you should be able to have the fixture closer to the canopy than an HID light (those throw off massive amounts of heat). The tagline for that web page is misleading though because it indicates that the bulbs are Metal Halide which they're not. Just looking at the stats of the number of Lumens etc, it appears as though you should have enough foot candles.

I hope that helps you out.

Cheers,

Gerard.

As everyone probably knows, I grow everything indoors due to weather and lack of a protected space outdoors during nice weather. My husband just hung a few shop light fixtures for me, which are each 48" in length and take 2 tubes each, either T8 or T12. The fixtures are "instant on, quiet running, and 0 degrees cold starting", according to the box. I'm using one warm tube and one cool tube in each fixture.

I've only had them up for a couple of weeks, and I can see a marked difference in my plants, already! Prior to this, I was dependent on the natural sunlight of an east window, coupled with a few small, and rather cheap, grow light fixtures purchased at a home store.

I'm not certain how much the shop fixtures cost, but I know they weren't really outrageous. I've got them hung on chains, so they can be lowered or raised according to plant height. Hanging them has made a big difference in what I can grow, and how it grows during the colder months!

The fixtures are plugged into timers, so they go on and off on a schedule.