# 4ft 6 bulb HO T5 too hot for seedlings in 4x2 veg tent?



## jsmits420 (Sep 16, 2013)

How's it goin everybody?  I recently got a new HO t5 for a really good deal and I don't understand why it's so hot when all I've read is how you can put them super close to your plants and they're amazing and aren't hot at all? But man I have better luck with my exhuast fan hooked up to my 1000w HPS that's got an air cooled 8" hood for my 4x4 flower tent than this thing.  I just germed 10 Nirvana Northern Lights seeds and they went into soil in solo cups tonight and after setting everything up, about an hour later I went and checked on everything like usual to make sure everything was fine, temps and humidity were good, everything working properly, etc. but the temp was higher than I'm used to. Now it might be ok, it was 81 and humidity was 43%.... but I like it around 75 and 45%. So humidity was about perfect, but I don't know what's up with this t5??? I wonder if it's just that it covers literally my entire veg tent, and there's nowhere for the exhaust fan to pull out the hot stagnant air (yes I had to put the exhaust fan mounted at the top to try and remedy this heat issue when I didn't think it'd be a problem).  But I have 2- 2' ho t5s with 4 bulbs that put out 8000 l a piece so I'm sitting at 16000 l for 8 sq. ft. So, I'm a little under what I tend to like for my veg numbers. I like to be at about 3500, sometimes closer to 4 for this bushy growth and tight spacing.  It might be the tent, it might be the light, but I'm just looking for suggestions here so I can either fix the problem or upgrade to an MH for veg. And having never run a MH before and since I have the lumatek dimmable ballast that can run HPS/MH, should I just get a 1000w MH and run it at 600w in my veg tent? Would that be too much? Or should I just run it in my flowering tent and swap out the bulbs after veg and once I get paid here soon I can get a new, smaller t5 or preferebly a smaller MH setup/hood if they will give me bushier faster growth for my veg tent and just keep my clones and mothers in there since I'm about to start cloning and keeping mother plants. I'd like to keep a continuous crop coming in every few weeks so I'm gonna need another MH setup or a smaller t5 fixture... Sorry for the whole book I just need to figure this out like yesterday because I have them under insufficient light than want I want and I don't want stretching. So worst case scenario I'll run to my hydro store and get a MH bulb currently, or just get a new MH setup.  Would 400 be plenty fora 4x2x5 tent and will that tent be adequate for a couple mothers and clones? Thanks in advance!!! Grow journal will be up after I remedy this and get everything rolling smoothly!!:icon_smile:

EDIT: I didn't really clarify but I took the 4 footer out and put the 2 2 footers side my side since they're 2x1 dimensions because it was just getting hotter and hotter the longer the light was on. When I finally said nope not doin' this is when it hit 84 and I didn't want to get any higher. That's why I say my lighting/space is inadequate. I need some assistance from MH veggers!!!! Thankssss!


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## jsmits420 (Sep 16, 2013)

I'm thinking maybe 2 150w mh's in the 4x2 tent so I can lower/raise for clones and mother's?  But I'm open to suggestions.


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## Auburn1985 (Sep 16, 2013)

I've tried running  a 4' 6-bulb T5 in my 2x4x4 veg tent, and it gets too hot in there.  So I removed 2 of the bulbs, and things seem to be doing much better.

Several very successful growers on this site use 4' 4-bulb T5 lighting in their 2x4 veg tents.  THG and pcduck come to mind.  Maybe they will chime in here and give you some advice.


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## oldsman (Sep 16, 2013)

i run an 8 bulb 4' T5 in my 2x4 space outside in a shed.On 95 degree days it gets to about 86 with just a oscillating fan blowing.You are only 6 degrees above what you like which I don't think is going to be detrimental for your girls.I like my veg area to run a little warmer than my flower area,seems my clones do better with a warmer temp.


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## jsmits420 (Sep 16, 2013)

Ah ok. Well that makes me feel better. I kinda wanted to try mh because I've read of bushier growth and my local store is having a customer appreciation week so everything is 20% off. That's whyni figured heck why not run a 400mh in there with an air cooled hood
 But I'll def take two bulbs out first.  Because I've had good results with my t5 before just in a bigger tent....


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## The Hemp Goddess (Sep 16, 2013)

jsmits420 said:
			
		

> I'm thinking maybe 2 150w mh's in the 4x2 tent so I can lower/raise for clones and mother's?  But I'm open to suggestions.


 
I don't think that there is any way that 2 150W MH will be cooler than a 6 tube T5.  You may want to do like Auburn says and only run 4 tubes.  You should, however, always be running an exhaust fan.  Exchanging air isn't just for heat control.  Your plants needs a continual supply of fresh air all the time the lights are on for proper photosynthesis.  If your space is getting that hot from the T5s, I think your ventilation system needs some work.  Tell us more about exactly what you have and how it is set up.


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## jsmits420 (Sep 16, 2013)

I just want to maximize light in that size without sacrificing air flow or heat.  That's why I was leaning toward mh..I would get a 400w mh air cooled setup for around 250 or 3 and money isn't an issue right now.


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## jsmits420 (Sep 16, 2013)

It's a 4x2, with the fan mounted at the top sucking air air. One long rectangular passive intake, then I was using the two side holes intended for ducting as passive intakes. My fan is sucking that thing through. .and since I moved the two other t5s in there I woke up this morning and they'd not gotten over 77 degrees with the lights about 4 inches away from the cups.  And with the 4 footer I had it about a foot and a half up just trying to get the temps down but they just kept rising
.there's no space around the light that's why I say I wanted a new fixture. I feel it's preventing the hot air from rising other than through a small MAYBE 1/4" crack at the 2ft side of the light..so I just think it's restricted.  Like I said, I never had issues with the 6 bulb in the 4x4. There was adequate room for air circulation.  I feel as though the light is keeping all the heat below the fixture and my 2 fans are just blowing around hot air. Thanks for the reply thg. I'm thinking of picking up a 4 bulb sunleaves t5 fixture from my local store since it's 20% off this week.


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## jsmits420 (Sep 16, 2013)

My htgsupply fixture doesn't let me run just 4 bulbs? only the two middle ones light up.  -_-


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## jsmits420 (Sep 16, 2013)

Sweet I called htgsupply and told them what was going on with the heat and the bulbs and they said it sounded like a faulty ballast. But my fixture was faulty, so I guess not sweet and I'll be running these 2 footers side by side and as close as possible so I cut down on light dispersion. I bought that light foreverrrr ago so PROPS to HTGsupply.  So they're sending me the 4 bulb AND paying to ship my 6 bulb backand refund me 125$ and I'll have it Wednesday. . I'm gonna run the 4ft 4 bulb with 20k lumens and my 2- 2 footers as side lighting and that'll put me at 36000L for 8 sq. ft. Perfect. 4500 L/sq.ft. but I might just run the 4 footer and see how that does . But I feel like 20000L for 8 sq.ft. isn't enough.  Don't I need to be around 3k-3500/ sq.ft.? Glad everything worked out!!


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## budz4me (Sep 16, 2013)

For vegging 3500 is ok, 5k for flower...those are of course minimum ideal parameters.


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## jsmits420 (Sep 16, 2013)

Yea I'm an over achiever lol. I'd like to hit 4 or 5 for veg and 7-8 for flower. I need me some big tight meds that'll last and have high thc content.  I have very chronic back pain. Thanks for the input!


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## Locked (Sep 16, 2013)

This is just my opinion, but don't waste your money on a MH setup. More lumens in Flower is always nice. I like to shoot for 7500. Not sure I would run more than 10,000 a sqr foot. Ho T5's work so well in veg that being slightly under 3000 a sqr foot is not an issue. I have been running 20,000 lumens in my 2x4 tent for a couple years now without issue. Still get nice squat plants with min stretch.


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## Auburn1985 (Sep 16, 2013)

jsmits, another thing to consider in favor of T5 over MH for vegging...

If you're running a perpetual setup, with vegging in one tent and flowering in another (at the same time), your flowering cycle will run much longer than your vegging cycle.  So, although MH may help your vegging plants grow bigger faster, you have extra time so using T5 won't hold you back...it will, however, save you money and heat issues.  IMHO.


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## jsmits420 (Sep 16, 2013)

HL- that's exactly what I'm doing. I called htg and they were super cool about it because there was something up with the ballast in my 6 bulb fixture.  So they sent out a 4 ft 4 bulb today and I'll have it Wednesday.  So props to them and great business! Also, they're paying to ship back my t5 and letting me keep the bulbs! So I'll have extras. Right now my tent is sitting at 75-77 with humidity from 45-56 (lows/highs resp.) Bu5 I've been told to up the humidity for my seedlings since they just went into solo cups of promix yesterday.  I picked up a cheap-o humidifier but do I need to put it in the tent? Feels like a dumb question because moisture plus hot bulbs doesn't seem like a good idea. My new place had a brand new central air unit and I've NEVER had the issue of humidity being too low lol. So that's what makes growing so fun, it's always changing and ya gotta be on your toes! This hum is exactly where I want it for flowering though, so I might take back the humidifier tomorrow and snag some humidity domes for like 10 bucks since I doubt I'll be using the humidifier very long after their little heads pop up. But I may be wrong. Veg/flowering humidty is supposed to be 40-60% is what I've always read right?


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## The Hemp Goddess (Sep 17, 2013)

Auburn1985 said:
			
		

> jsmits, another thing to consider in favor of T5 over MH for vegging...
> 
> If you're running a perpetual setup, with vegging in one tent and flowering in another (at the same time), your flowering cycle will run much longer than your vegging cycle.  So, although MH may help your vegging plants grow bigger faster, you have extra time so using T5 won't hold you back...it will, however, save you money and heat issues.  IMHO.


 
Actually, the time between when I put a seed in dirt or a cutting in the cloner is about the same amount of time it takes my plants to flower.  It takes a bout 2 weeks+ for a cutting to root and then another 7 weeks in veg is about right for me.  Also, IME, I have not found MH to veg any faster or better than T5s.  In fact, because T5s run cooler, can be kept closer, and spread the light better, I believe that they do a better job than MH.


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## jsmits420 (Sep 17, 2013)

Thanks Auburn, but I have to agree with THG for this specific example. I veg for 6 weeks typically, and that's after germination etc. But this current grow is flying I feel like. Tried a new germination technique, the glass of water, and all 10 sprouted tails in 48 hours and into some promix with a little bit of happy frog they went. Solo cups, I might add, for the first few weeks until they're ready to finish out veg in their 1 gal smartpots for another 5 weeks or so. But I typically veg, like I said, for about 6 weeks. But these will be longer because I'm gonna do some training this go around, so I might be looking at 8 weeks veg time total from seed. So that would be 8 weeks veg/8 weeks flower. Rough estimate. So they'll be about the same time for me as well this go around. But everyone is different. And every plant is different. So who knows. These might take off on me and only veg for 5 weeks! The waiting game begins   But I understand what you mean Auburn- once I get my setup going I will be vegging for less time and every 3-4 weeks I'd like to be flipping a few more plants, while taking out a few plants so I get constant medicine every month. I still have a lot of reading to do on that subject though. But to the original post, we found the issue-it was my fixture. I'll have my new one Wednesday, the 4 ft 4 bulb, so I can take these 2 footers out since they're a pain to deal with!! (only having one set of height adjusters so I'm tying the other light up so it's a pain to keep both of them even.) But I'll have pictures up ASAP I'm getting a new camera today or tomorrow so it'll be just in time for Wednesday. Fingers crossed I have 10 cups with cotyledons sun bathing when I start the journal!!!


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## jsmits420 (Sep 17, 2013)

The Hemp Goddess said:
			
		

> Actually, the time between when I put a seed in dirt or a cutting in the cloner is about the same amount of time it takes my plants to flower.  It takes a bout 2 weeks+ for a cutting to root and then another 7 weeks in veg is about right for me.  Also, IME, I have not found MH to veg any faster or better than T5s.  In fact, because T5s run cooler, can be kept closer, and spread the light better, I believe that they do a better job than MH.



And yes THG, I will be sticking with my T5s. I just had a malfunctioning fixture but that has been addressed. Thanks for all the help and I hope you pull up a chair come Wednesday when I get my journal up and running! Hopefully everything goes nice and smoooooth But if not, I'll be looking for you!  haha


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## Auburn1985 (Sep 17, 2013)

jsmits420 said:
			
		

> Thanks Auburn, but I have to agree with THG for this specific example. I veg for 6 weeks typically, and that's after germination etc. But this current grow is flying I feel like. Tried a new germination technique, the glass of water, and all 10 sprouted tails in 48 hours and into some promix with a little bit of happy frog they went. Solo cups, I might add, for the first few weeks until they're ready to finish out veg in their 1 gal smartpots for another 5 weeks or so. But I typically veg, like I said, for about 6 weeks. But these will be longer because I'm gonna do some training this go around, so I might be looking at 8 weeks veg time total from seed. So that would be 8 weeks veg/8 weeks flower. Rough estimate. So they'll be about the same time for me as well this go around. But everyone is different. And every plant is different. So who knows. These might take off on me and only veg for 5 weeks! The waiting game begins   But I understand what you mean Auburn- once I get my setup going I will be vegging for less time and every 3-4 weeks I'd like to be flipping a few more plants, while taking out a few plants so I get constant medicine every month. I still have a lot of reading to do on that subject though. But to the original post, we found the issue-it was my fixture. I'll have my new one Wednesday, the 4 ft 4 bulb, so I can take these 2 footers out since they're a pain to deal with!! (only having one set of height adjusters so I'm tying the other light up so it's a pain to keep both of them even.) But I'll have pictures up ASAP I'm getting a new camera today or tomorrow so it'll be just in time for Wednesday. Fingers crossed I have 10 cups with cotyledons sun bathing when I start the journal!!!



Well, definitely go with what THG says.  I've read enough on this site to know she knows what she's talking about.  She's got the respect of everyone here, including me.

I only grow feminized seeds.  And it just seemed like my previous grows from seed to end of veg were 7 weeks, and my flowering times were 9 weeks (AK47 and Northern Lights).  I used a 400-watt MH in veg for those grows.  Now I'm using a 4' 4-bulb T5 in veg for the first time.

Sorry.  I wasn't trying to spread mis-information.  Guess I should refrain from giving advice until I've got a few more grows under my belt.


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## jsmits420 (Sep 17, 2013)

Nah you're good. The advice you gave was accurate and good information to my knowledge. I was just say saying I could see it from both perspectives. If you train your plants and give them another week or so, certain strains COULD be equal in veg and flower time. And I was agreeing with both of you. THG for this particular grow because it'll be my first time training my plants. And also starting up a perpetual grow cycle where I keep my veg tent full with 1-2 mother plants to clone from so I can get some good practice cloning. But you were both right, I wasn't saying you were wrong. Sorry if you took it that way. Nothing but respect!


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## Auburn1985 (Sep 17, 2013)

jsmits420 said:
			
		

> Nah you're good. The advice you gave was accurate and good information to my knowledge. I was just say saying I could see it from both perspectives. If you train your plants and give them another week or so, certain strains COULD be equal in veg and flower time. And I was agreeing with both of you. THG for this particular grow because it'll be my first time training my plants. And also starting up a perpetual grow cycle where I keep my veg tent full with 1-2 mother plants to clone from so I can get some good practice cloning. But you were both right, I wasn't saying you were wrong. Sorry if you took it that way. Nothing but respect!



Thanks man.  I'm looking forward to following your grow journal.


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## jsmits420 (Sep 18, 2013)

I'm looking forward to starting it and getting some pictures up because so far it seems like it's all talk! And apparently I thought HTGsupply would ship the fixture out Monday if I paid for it, then they'd refund me plus the additional difference from the 6 bulb fixture, like they said..... and guess what? It didn't ship until today! I'll have it Friday, so I'm not **'ing guys, the journal WILL be up Friday unless ( with my luck ) something happens with the delivery. Lol gotta love ol Murhpy!


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## Jper6647 (Sep 20, 2013)

Whats the dif in T-5 and reg florescent bulbs.  Ultimately isn't it about the type (being fluorescent) and the power/lumes?


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## WeedHopper (Sep 20, 2013)

The Hemp Goddess said:
			
		

> Actually, the time between when I put a seed in dirt or a cutting in the cloner is about the same amount of time it takes my plants to flower.  It takes a bout 2 weeks+ for a cutting to root and then another 7 weeks in veg is about right for me.  Also, IME, I have not found MH to veg any faster or better than T5s.  In fact, because T5s run cooler, can be kept closer, and spread the light better, I believe that they do a better job than MH.


 :yeahthat:


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## Jper6647 (Sep 20, 2013)

Whats the dif in T-5 and reg florescent bulbs. Ultimately isn't it about the type (being fluorescent) and the power/lumes?


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