T5s for Phal Seedlings

[Undergrounder]

OK so i'm new to T5s... and lights... pretty much everything.

I have a shelf system where i plan on growing Phalaenopsis seedlings. There are 2 shelves (3 including the base), and i plan on suspending a thin T5 fixture under each shelf (and one on top) to create three levels of growing space, each level with its own T5 lights. I hope that makes sense.

Anyway doing this, the Phalaenopsis would probably be just 10cm or so away from the lights, and i would like to know how powerful my lights need to be at this distance. I could get 2, 3, 4 or even 8 bulbs per shelf, and those bulbs would be either 28W or 54W, depending on the make of the lights.

I don't want to burn the things, but i need good light... so how many T5s (at 28W or 54W - depends on the maker) should i need for Phalaenopsis seedlings at about 10cm distance?

Thanks!

[calvin_orchidL]

In my opinion, 28W T5s are useless - you might as well just go with the cheaper T8s

10cm is pretty close for T5s, and for seedlings...for reference, my phal. equestris is nearly 2ft below a bank of 4 T5s and shows redness around the leaf edges as well as prolific root growth.

Hope that helps!

[Undergrounder]

it does thanks calvin i had no idea they were so strong.

T5s are hard to find here in Australia, particularly for growing plants. Even T8s aren't easy to find, other than the kind you find in hardware stores that you need to wire yourself. There's not a large range of fluoros in general at all, and they tend to be expensive. Acually the only reference i can find to T5s is in aquarium setups, where you'd need to swap out their 10k lights for a lower spectrum mix. The thinner size of the T5s is important to me as well in a shelf setup where space is limited.

Anyway since they're so close tho, i wonder if the 28W ones wouldn't actually be better.. If i were to go the 54W though, i could actually have just one or two on at a time.

if it helps, the kind of thing i have in mind are:

T5 AQUARIUM OVERHEAD LIGHT 4x54W Hi Output 120cm Long - eBay Other Supplies, Fish, Pet Supplies, Home. (end time 26-Sep-08 21:12:13 AEST)
(4 X 4-foot 54W T5)

and

Aquarium Light Aquathrive Aluminium 4ft Triple T5 - eBay Other Supplies, Fish, Pet Supplies, Home. (end time 26-Sep-08 21:45:11 AEST)
(3 X 4-foot 28W T5)

and

4FT Double T5 54W High Output Aquarium Aluminum Light - eBay Other Supplies, Fish, Pet Supplies, Home. (end time 12-Oct-08 10:19:24 AEST)
(2 x 4-foot 54W T5)

so.. maybe a single T5 54W or even up to a triple T5 28W?

[calvin_orchidL]

I'm sure other people with experience with T5s will chime in soon but I think cost is a bit of an issue...for seedlings, I would go with T8s simply because they are so much cheaper, would do the job fine. These *should* be available as things called "shop-lights" from any big hardware store...they're very common and in fact, most fluorescent lighting in offices and homes are either T12s or T8s. T5 bulbs (for cheap) are a little annoying to buy as well...at least when you're not in the states, there are limited places that sell them.

In terms of the thinness of the bulbs, the main advantage of that is so you can pack more of them together over a smaller area, thus increasing the foot candles (units are light intensity over area) which is helpful for growing high light stuff. I'm estimating you can fit 3-4 T5s where two T8s would fit...(I could measure and compare my fixtures for you when I get home, althouguh I have a feeling this info may be available online) but then again, 2 T8s for seedlings should be enough light (in my opinion at least )

As for going with a single T5, that's good but you're dealing with a very narrow strip of light. Depending on how high you mount it from the seedlings, you could be getting an uneven distribution of light on your grow shelf, with a lot near the middle and less towards the edges...for seedlings, which I'm imagining a more uniform light across the entire shelf might be desirable (since I'm envisioning a lush shelf crammed full of phal seedlings ) two lights set over the entire shelf may be a better option. But it does depend on the shelving etc...

hmm...I seem to be babbling. Hope this makes sense and isn't even more confusing.

[Royal]

Good insight Calvin. Babble away.

Do you go with the shoplight style T8's or do you get the direct wired fixture?

[Ross]

I'll chime in. T8s should do the job just fine with seedlings, but what about as the plants mature? If there is no way to move the lights, then t8 is your best bet. 10cm (4") is really close for most lights. At that distance I would almost recommend t12s.

[Undergrounder]

thanks for the help everyone..

the reason they're so close is that they're in a shelf-type setup and if i want three grow levels, they need to be about that close. Maybe 15 - 20cm max..

Also im not too worried about the space they take up horizontally, just the space they take up vertically. For instance a T8 fixture is about 8 - 9cm high (for a standard baten), while a T5 is only about 4 - 5cm high. So less space the lights take up, more space the plants have to grow, or more space available between them and the fixture.

As they grow older i'll move them over to another table i have which just has a couple of hanging CFLs, and plenty of grow room.

If i do go with the T8s (which are sounding like the way to go) i just need to wire them up, which is a pain.

[calvin_orchidL]

Royal - I use shoplights mainly the cheap ones are only 25-35 bucks a pop and the bulbs are around 4 dollars canadian each...hard to beat that!

Undergrounder - not sure if you have homedepot down south, but lots of hardware stores carry them. Here's a link - no wiring nesessary! Just plug and play

[Undergrounder]

yeah sorry Calvin, no homedepot, and not many hardware stores carry them, the cheapest pre-wired with a plug ones are single t8s for about $50.

Think i'll go for the triple 28W t5. If they're as bad as you say they are they should be less likely to burn, plus i can turn each tube on individually and/or put something under them to diffuse the light if necessary. They're cheaper than t8s anyway.

[Ross]

Originally Posted by Undergrounder

yeah sorry Calvin, no homedepot, and not many hardware stores carry them, the cheapest pre-wired with a plug ones are single t8s for about $50.

Think i'll go for the triple 28W t5. If they're as bad as you say they are they should be less likely to burn, plus i can turn each tube on individually and/or put something under them to diffuse the light if necessary. They're cheaper than t8s anyway.

Are those HO (high output) t5's? T5s should do fine. If they are too bright (the leaves turn red) then just hang a gauze curtain between the lights and the plants until they mature.