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CFLs...T8s...Best choice?

Roguejim

Roguejim

I'll start with the details:
My grow space for my seedlings measures 2'x4'. ( I actually have 2 spaces of the same size, but, let's just deal with one.)  I am running 3 T8 fixtures in the one grow space, each fixture holding 2 tubes.  Each tube is 32 watts, 6,500k.  Total watts = 192.
 
Can I cover this same space with CFLs without exceeding 200 watts?
 
Do plants grow faster under CFLs than under T8s?  If not, why change to CFLs?
 
I have not abandoned the MH option from my other thread.  Just trying to understand the appeal of CFLs.
 
I think preference has a lot to do with it, and working with what you already have on hand. If someone already has a bunch of clamp lights or sockets, then CFL bulbs would make sense to use. Or if they are trying to aim all of those lumens into a tighter  spot, like in a grow tent, or underneath a plant canopy.
 
In your case i don't think you'd get any major advantage by switching to CFL. You have 6 T8 bulbs with a combined 17,000 Lumens over a 2' x 4' area, this is pretty good for seedlings and starts. You can try doing the lumens + watts math, i tend to go to a bulb website to get those numbers to help me make my decision.
 
But again, in your specific case, i think the only true upgrade would be HID or maybe LED ($$$). HID + HPS throws out a ton of lumens per watt, the 250w models for example are 33,000 Lumens, which is nearly double your current light setup, and only using 50 watts more. CFL won't give you anywhere near such a dramatic difference.
 
Edit: and here's a CFL vs HPS grow comparison: http://www.3ch.co.uk/hps-vs-cfl/info_104.html
 
if you're buying new it might be nice to just get CFLs, why?
No ballast that can fail, No big fixtures, smaller footprint, easier to replace/handle/store
 
a 32W CFL produces 2000 lumens, whereas t8 32w produces 2800, so cfl is actually less efficient at comparable wattage.
 
If you start thinking about LEDs you have to throw lumens out the window because red / blue lights will scale differently than white. I'm going to be trying 60w per 4x2x2 area with LED once i get everything set up.
 
Jetchuka said:
I think preference has a lot to do with it, and working with what you already have on hand. If someone already has a bunch of clamp lights or sockets, then CFL bulbs would make sense to use. Or if they are trying to aim all of those lumens into a tighter  spot, like in a grow tent, or underneath a plant canopy.
 
In your case i don't think you'd get any major advantage by switching to CFL. You have 6 T8 bulbs with a combined 17,000 Lumens over a 2' x 4' area, this is pretty good for seedlings and starts. You can try doing the lumens + watts math, i tend to go to a bulb website to get those numbers to help me make my decision.
 
But again, in your specific case, i think the only true upgrade would be HID or maybe LED ($$$). HID + HPS throws out a ton of lumens per watt, the 250w models for example are 33,000 Lumens, which is nearly double your current light setup, and only using 50 watts more. CFL won't give you anywhere near such a dramatic difference.
 
Edit: and here's a CFL vs HPS grow comparison: http://www.3ch.co.uk/hps-vs-cfl/info_104.html
Click to expand...
 
This may seem dumb, but, would I see a dramatic difference in plant growth between 17,000, and 34,000 lumens?
 
Roguejim said:
 
This may seem dumb, but, would I see a dramatic difference in plant growth between 17,000, and 34,000 lumens?
Click to expand...
Not dumb at all, and the answer is yes if it's HPS or MH. Results vary, but 250 watts is 100 watts more powerful than the HPS in the review i linked.
 
In that review a 250 watt CFL @ 15,000 lumens squared off against a 150 watt HID @ 16,000 Lumens.
 
Also remember the 50 extra watts on your power bill + $140 for ballast and bulb. You may be better off holding on to your T8's if it's only for springtime starts(?)
 
Why not go to t5 ho? CFLs and T8/12's are junk in comparison for veg stage to get an early start on the season. If you want to flower and fruit go HPS,
 
Jetchuka said:
Not dumb at all, and the answer is yes if it's HPS or MH. Results vary, but 250 watts is 100 watts more powerful than the HPS in the review i linked.
 
In that review a 250 watt CFL @ 15,000 lumens squared off against a 150 watt HID @ 16,000 Lumens.
 
Also remember the 50 extra watts on your power bill + $140 for ballast and bulb. You may be better off holding on to your T8's if it's only for springtime starts(?)
Click to expand...
I can tell you that 150 watt HPS in the link blows away my T8s, and it's using less watts, less lumens.  Why?
 
Roguejim said:
I can tell you that 150 watt HPS in the link blows away my T8s, and it's using less watts, less lumens.  Why?
Click to expand...
they are only covering 2x2 area while you're covering 4x2 also your lights dont have nice reflector on them like the hps does?
 
Are you going for full seedlings to fruit? or just seedlings till they go outside?
 
Roguejim said:
I can tell you that 150 watt HPS in the link blows away my T8s, and it's using less watts, less lumens.  Why?
Click to expand...
I think OKGrowin was right with his response. I have also heard that HPS+MH light carries further than CFL and T8 before it breaks up (better light penetration).
 
So it might be all of the above.
 
OKGrowin said:
they are only covering 2x2 area while you're covering 4x2 also your lights dont have nice reflector on them like the hps does?
 
Are you going for full seedlings to fruit? or just seedlings till they go outside?
Click to expand...
Just until plant out.  If I HPS/MH, I'll probably just go the whole enchilada, and buy a 400-watter.  If I'm going to spend the $$, I want to see the difference.  $20-23 a month for four months isn't a big deal..
 
you'll be able grow plants year round if u get the 400 watter lol, HPS is great for fruiting as you can see in that link up there.
 
most people get fluorescent or cfl to just start the seedlings as the light is more spread out and is less hot. you can't really put a MH or HPS on a shelf 10in away from your plants like you can the fluorescent/LED. 
 
Thanks, but I'm not sure I understand why it matters if I have to keep a HPS bulb further away, unless I had a height restriction in my grow area, which I don't. Do you think it is overkill to run a 400/watt HPS/MH over seedlings? They would certainly grow considerably faster and bigger, or am I wrong? Thanks.
 
Roguejim you're not wrong, and there are many here that use 400 watt HPS/MH (or higher) on their seedlings. You just need to be able to accomodate the light assembly and the added warmth, but it sounds like you have those bases covered.
 
The increased growth rate can be used to your advantage in a few ways: you can start seedlings a couple of weeks later. Or you can run a couple of hours less light per day etc etc.
 
And if you have a favorite plant that begins fruiting in the Fall, you can bring it inside and finish it under lights and have a harvest in November / December.
 
Is the total area covered by say, a 250 watt HPS, largely the result of the reflector, or something else? Would a 250 watt HPS adequately cover a 3'x3' area, or even a 4'x4' area?
 
RogueJim, i'd say it's a few things, a result of the reflector, reflector shape (square, circular, rectangular), and wattage.
 
I cannot answer your second question with any first hand knowledge, so take the following info with a grain of salt: With seedlings and starts i'd say that 4ft is the max while trying to maintain some of the high growth rate we've spoken of. Whereas 3'x3' would almost certainly maintain the high growth rate, and support full sized fruiting plants within that same space.
 
Hopefully someone else with experience can chime in.
 
Thanks, I'm not interested in supporting fully grown plants, just seedlings for 4-5 months.

The issue I'll be facing real soon is that my 40 seedlings I have in Solo cups, now, will outgrow the 2'x4' area once I plant up into #1 pots, plus I still have annuums to plant in a month. So, do I buy a 250 watt HPS, or buy 2 more T8 fluoro ballasts? If I just buy 2 more T8 ballasts, the wattage will now be 320.
 
If your going to get an hid get at least a 400 watt but remember bigger is better. I got really nice plants last year with one but I'm diehard on t8s too. It really depends what you wanna do and your pocketbook. If your just trying to give them more light cause they outgrew what you have buy another but if you want ten or twelve nice plants get a hid and poke em under. You'll be amazed what a hid can do vs t8 bro.
 
It looks like a 250 watt HPS wil put out 27,000-33,000 lumens.  That's not much of a hit on my electric bill, and I'd still have the T8s, if needed.  So, it's just a matter (I think) of how much area the 250 watt HPS would effectively cover.  If I'm calculating things correctly, I'd have to have around 6 T8 ballasts(2 tubes each), side by side, to equal 33,000 lumens over a given area,  The wattage would be 384!  
 
Roguejim said:
It looks like a 250 watt HPS wil put out 27,000-33,000 lumens.  That's not much of a hit on my electric bill, and I'd still have the T8s, if needed.  So, it's just a matter (I think) of how much area the 250 watt HPS would effectively cover.  If I'm calculating things correctly, I'd have to have around 6 T8 ballasts(2 tubes each), side by side, to equal 33,000 lumens over a given area,  The wattage would be 384!  
Click to expand...
 
I'm running T5's and getting ~ 101Lumens/Watt. Close to the efficiency of of an HPS, a ton less heat, and cheaper for me to set up with a little DIY. They're also much more shelf-friendly for stacking vs spread out on the floor. Just food for thought.
 
Light and fixture:
http://www.lowes.com/pd_162635-337-SNF228T5_0__?productId=3339554
http://www.payless-4-lighting.com/f28t5-865.html
More info on bulb:
http://www.elightbulbs.com/Eiko-07150-F28T5-865-Straight-T5-Fluorescent-Tube
 
I plan to have two fixtures (4 bulbs total) per shelf for 112watts/shelf x 4 shelves = 450w total.
That gives 32ft^2 of lighting with ~11,200 lumens per shelf, or 1,400 lumens/ft^2.
 
Cheers,
Spork
 
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