Ok so I was originally vegging using 2 38w T8 tubes (6500k) and decided that I wanted to try CFLs because they provide more lumens per sq/f. I got some 26w 6500k CFLs with large reflectors and put them about 6 inches above plants. Burned the shit out of them so I bumped them up to 8 inches. Still burning, so I had to move them to a foot above the plant. With the Tubes I could have the bulbs RIGHT up on the plant with no risk of burning. My question is, would 2 of the tubes allow the plant to grow faster because they are so close or are the CFLs still more efficient at 1 foot away?

That's odd, what kind of air-flow have you got? The CFL's put out alot of heat but as long as you've got airflow it's ok to have them really close.

I used to have my CFL's 2 inches away from the plants, and that was 500w of CFL.

Ive got a 125w cfl about a cm away from my plants with no burning. Could be the reflector pushing the heat down like a diamond one does.

I have a small fan blowing the heat away directly at the cfl.

Tubes are far more efficient and cheaper in the long run.

Enviro's lose 1/2 there light out the top, given fluro's have such piss poor penetration in the first place reflectors are pointless. CFL's like enviros should be hung vertically IMHO.

I use an enviro but when it breaks will be replacing with 4 foot 6500k tubes.

Little trick get a small strip of foil tape (The heat proof stuff) and stick it across the top of the tube, mini reflector seen it on overgrow used many times to no ill effect.

erm.... what?

When you say "vegging", what do you mean exactly.

In my humble opinion, a 250 watt HPS is the best lamp for seedling to approx 4 weeks of any grow.
(well, a 70 or 150 watt would be useful too, but that's taking optimisation a little too far.)

I found I could have my 18 watt CFLs within a thumb's width of my seedlings :-

Click to view attachment

no way was any cfl burning your plants from anything more than an inch or two away. i'm guessing nute burn, or deficiency or water stress, i.e. too little

Thats exactly what it is, the big ass shiny reflector is hot :|


Trust me, it was actually burning. Still waiting for an answer to original question :|

We've answered your question and more. Some of us have years of experience at this game whereas you've been here 5 minutes and are complaining already.

Basically no one can figure out how you're managing to burn plants with 56 watts of fluorescents of any kind - your air movement must be unbelievably crap.
The photo I posted earlier was of 144 watts of 18 watt CFLs as close to 8 seedlings as it was possible to get.

Your 56 watts of CFLs should be slightly less crap than the 36 watts of old-school tubes - depending on how many plants you're trying to squeeze under them.

What sort of lamp are you flowering under ? Personally I found my 144 watts of CFLs were barely good enough for 2 weeks ..at which point I put them under a 250 watt HPS at 9 inches.

Click to view attachment

In fact I prefer to put them 9 inches from a 250 as soon as they've sprouted.

Are you over-feeding your plants and drying them out that way - like putting salt on a slug ?

Or is your extraction so good you're dessicating them. ?

Why not post a photo ?

I did a grow with cfl's, thumb width above, no air flow at all, not even close to burning...... i even cut up soft drink cans and had them over the cfl's as reflectors (was awesome btw) which produced a lot of heat and still not even close to burning them...i have no idea what your issue is.

ive got 180w of cfl no more than 3cm above buds and not one pistil has burnt ! its not a light issue

I've stated what the issue is, I am using the large metal diamond reflectors.

The only question I asked was what would be more efficient, 2 38w fluoro tubes right above the plant or 2 cfls 26w 1 foot above the plants.

Between the 2 metal contacts either end of the tube, cut a 1-1.5cm strip of silver tape as long as the tube and stick it to what will be the top of the tube (Hardest part) then the inside silver lining of the tape acts as a mini reflector along the length of the tube. The heat build up inside the tube is minimal and the light is considerably brighter even than with thw store bought T5 reflectors.

Wow, that sounds like a great tip. You think this will be more efficient than a 26w cfl 1 foot above the plant with a large reflector?

Why not just dump the reflectors ?

My 8 x 18 watt CFLs were simply mounted on a seed tray-sized piece of mylar-backed plasterboard.

Click to view attachment

If I ever grew again, I would probably make a different lamp using the long / thin type of CFL - mounted horizontally - use fewer lamps and make reflectors ...

All being well, CFLs should be a fairly effective way of getting lumens to your plants - I've never done more than use foil reflectors with linears, but I still feel they're better suited to mums and cuttings ..

As you can see by my photos, I have never taken the "foil = hotspots" mantra at all seriously - I'm guessing that your lamps are simply in the wrong position under highly efficient reflectors (not being designed for them) and you do indeed have hotspots.

ide go for tubes three in a row, loverly juberly

What Tutu says.

I would have them at 4 inch's with a fan blowing between the tubes and the canopy of the plants.

I have had them at 2" before with no ill effects but if you don't visit for a couple of days they can grow into the bulbs then they will burn.

12" is far too far to put it in perspective I have a 1000w at 14" in a parabolic shade.

That's 40 times the wattage at 2" higher.


And yes tubes will be better, when my enviro goes bang I'm going to build a proper veg chamber out of 3"x2" and ply wood with 4 foot tube fittings probably 2 foot wide and 8 tubes, but I shall put them on 2 different circuits so I can have only 4 on at a time when in early veg and then power up as needed before going into a flower chamber to be vegged up under 600w's and then flowered under a 1000w