T5 18" bloom bulbs?

im looking every were online and i cant seem to find them anyone have any suggestions on were to look at, or were i can find some? my set up is not very big and i was gonna add more lighting since its getting kind of bushy in there.

Savage: 18"? Are you sure? I've seen them in 12", 24" and 4', but not 18". My friends tell me those are the standard sizes. Or are you dealing with some bizarre metric size outside of the USA? 24" is only 6" longer, are you sure you couldn't use another fixture in there? Hank

yea it was T8 18" so thats my bad i was looking for the t5 for awhile till my friend came by and told me im looking for the wrong thing

T8? Ew. The only tubes I would use are T5's. ESPECIALLY during flowering, as the plants will stretch upwards requiring more space between the lights and the bottom buds which will be severely underlit. Can you give us more details on your setup? It might be a good idea to redesign before you start flowering.

1 Warm Spectrum 200 Watt High Output Compact Fluorescent Grow Light
2 F15T8/WW Fluorescent 18" 15 Watt 3000K

i have the 200 watt cfl at the top and i the 2 t8 at the bottem so the bottem get light as well i have pictures posted at

http://forum.grassci...2-12th-day.html
there looking pretty good tho

T8? Ew. The only tubes I would use are T5's. ESPECIALLY during flowering, as the plants will stretch upwards requiring more space between the lights and the bottom buds which will be severely underlit. Can you give us more details on your setup? It might be a good idea to redesign before you start flowering.

i thought the the only difference between the t5 and the t8 are the size of the tube. t5 are smallest( there prongs are very close together, and bulb is very slim), t8 are alil bigger( prongs are further spaced apart because of size) and t12 the largest?

You got it backwards. T12's are the smallest, then T8, then T5. And is there a T10? I forget. Anyway, T5's are the most efficient and the brightest, therefore the best for growing. T8's are ok, but still not very strong. T12's are hardly worth it. Since they're not the main light source, I see nothing wrong with sticking with what you got. Try and find a color temp below 3000k if you can. The redder the better.

i have the 2 t8 at the bottem facing up is that good for them? because my main light doesnt penatrate the top anymore? i was think at least they get some light is what i was trying for.


ok now im confused i thought t5 = 5/8" inch, t8 8/8" inch and t12 were 12/8" or 1 1/2" inch. =) but finding a t8 with under 3000 was hard. ebay sucks and other places online they only carry t5 and t12 or t8 cw lights, but im thinking its alot of light for it hopefully i can find a redder t8 and get it next pay check..


buy the way if you happen to find one online thats trustworthy can you send me a link?

Edited by savage420life, 30 April 2012 - 02:53 AM.

I tried using the 18" tubes for growing. Not enough light. You can get em at walmart btw. However, I am running 8 cfl 26 watt daylight bulbs, and when I switch in a week I'm running 6 26watt cfl 2700k and 2 55watt cfl 2700k bulbs. The 26 watt have 1760 lumens each and the 55 watt has 3860 lumens. I'm only growing 2 plants. Unless you have the tubes within a couple inches of the plants they are not doing you any bit of good.

SERIOUSLY check out kamelredlights cfl guide in the absolute beginners grow section. He gave me an awesome amount of advice.

Edited by KalofKrypton, 30 April 2012 - 02:57 AM.

what your set up like? and my wal mart sucks, only light for t8 they have are t8 18" 8000k lights. i had two of them in the for veg and they really grew quite nicely, i had to trim a whole lot and finding out i didnt have just sativa in there sucks.

but your right it is good reading.

Edited by savage420life, 30 April 2012 - 03:08 AM.

i cnat post the pic again on this thread but heres a better link for ithttp://forum.grasscity.com/attachment.php?attachmentid=869498&d=1335643928

ok nvm i got it on here

i have the 2 t8 at the bottem facing up is that good for them? because my main light doesnt penatrate the top anymore? i was think at least they get some light is what i was trying for.


ok now im confused i thought t5 = 5/8" inch, t8 8/8" inch and t12 were 12/8" or 1 1/2" inch. =) but finding a t8 with under 3000 was hard. ebay sucks and other places online they only carry t5 and t12 or t8 cw lights, but im thinking its alot of light for it hopefully i can find a redder t8 and get it next pay check..


buy the way if you happen to find one online thats trustworthy can you send me a link?

Well I'll be damned, the internet agrees with you. I could have sworn...well anyway regardless of size, T5's are the most powerful and the preferred choice. 3000 is ok, and the placement is fine. If you can possibly raise them up closer to the plant, that'd be better but if not, they're still helping from where they are.

i apperciate it dude im always trying to learn and if i sound like a smart ass i really do not mean to. but yea im starting to understand what your saying. thanks for the feedback bro

what your set up like? and my wal mart sucks, only light for t8 they have are t8 18" 8000k lights. i had two of them in the for veg and they really grew quite nicely, i had to trim a whole lot and finding out i didnt have just sativa in there sucks.

but your right it is good reading.

You can buy the 18" daylight tubes from the "loose" bulb section. Where all the replacement tubes are. Says daylight right on the box.

Figured I would drop by real quick and let you know my opinion.

Ditch the T8's, HTGsupply carries T5's for VERY cheap. Just finished a grow with T5's and they are surprisingly effective. Yield isn't huge but you won't end up with fluffy, loose, stemmy buds. T8's are not very efficient bulbs, and don't emit enough intensity to get what you're paying for. There is a lot of wasted energy in a T8 bulb.

However, if I were going to use T8's to grow, I would make sure the color temperature is either 2700k or 3000k during bloom. A few minutes on google and you will be able to find some very cheap and easy. I tried to find a good vegetative growth T8 online, but the best temperature I could find was 5000k, which is somewhat close. 6400k is ideal for veg, but I suppose 8000k would do fine.

I use 2 T5 @ 6400k and 2 @ 3000k in my T5 4-bulb light, and I get fgood results, not to mention the light was only $100 including a $20 digital timer.

Edited by madamayo, 30 April 2012 - 05:20 PM.

yea im probably gonna switch lights one day but for right now, i think my main concern right now is will the lights i have now in the very limited space i have, will do the job. i see the t5 are better choice, but the dnot come in 18" and thats as big as i can go as of right now. so would a 12" t5 be better than a 18" t8? thats confusing a 24" t5 will not fit in my area as you can see. so thats another question. if you had this setup what would you change in it? besides a completely new setup( which will one day happen)

Personally I would ditch the tubes altogether and run 26watt compact fluorescents. So many more lumens and its focused. Seriously.

T5's that are 12" will do just fine for what you are looking for. I promise when you swap them out you will see a huge difference.

Beautiful picture! Although I can understand where you are coming from, I would have to disagree with using CFL's for blooming. They do a good job for veg, but you really need that light penetration for bloom, and you can't get that without some high output lights. T5's are incredibly efficient bulbs, but slightly more expensive. I would definitely recommend some CFL bulbs to start with on a budget, but CFL's simply cannot stand up to T5's.

CFL bulbs are decent bulbs, but T5 bulbs are without a doubt better. Less heat, more efficient, and more reliable color temp, only downside is they are more expensive. I currently am using a combination of T5 and CFL for my current grow box, but I only use the CFL for veg and that is because I have to. As soon as I can afford to I'm buying an HPS bulb, using my T5 for veg, and only keeping one CFL for my clones.

In your circumstances I would save the money for a T5 light instead of replacing with CFL. Not only is the difference in price only a week or two extra saving, your power bill won't take as hard of a hit with T5's. Running 24/0 I saw a $10 rise in my power bill.

CFL bulbs are decent bulbs, but T5 bulbs are without a doubt better. Less heat, more efficient, and more reliable color temp, only downside is they are more expensive.

You have just rocked my world madmayo. I never bothered to check how T5 output compared to CFL output in watts/lumens (equal color temp, of course) and you're absolutely right. And you cannot touch a CFL once it's warmed up, but as I understand it T5's aren't much warmer than a T12, which you can hold all day long. You could put a lot more light on top of a plant with T5's over CFL's. Tou che, salesman...

BUT, I must maintain that CFL's have one distinct advantage over T5's...mounting flexibility! Clamp lamps, twisty desk lamps, direct plug-in sockets, you can put these things anywhere. With some T5's overhead and CFL's picking up the lower branches, I think they'd make a great team! Cuz while T5's do put out more light, it's not much more so their range can't be that much better.

I'll have to try some when I get growing again.

yea i seen what your saying now my plants are starting to face down i dont think i have enough light in there so im thinking bout going to walmart and see what i cant rig up. thinking about just going with the cfls 55 watt. but how many would i need to have the right amount of lumens in the box?