# t5 vs hps heat



## rebel (Aug 13, 2011)

my space is 5' long, 7' tall and 16" wide.
rather narrow to suit me.

i have a vent or direct updraft at bottom and at top i have direct vent also.
dont have any intake or exhaust fans, got a small 10" fan blowing.
last yr tried a 600 hps/mh and was awful hot.
how would a 4' 4 bulb t5 do ?
veg, flower with the t5 ?
thanks all


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## HomieDaGrower (Aug 13, 2011)

A T5 does not have the light penetration to be a good flowering light, in my opinion.  It might be OK if you are flowering freshly rooted cuttings, and growing lollipops instead of a full plant.  I would just buy the fans and use the HPS.  You will get much better yields, with the HPS.  But you must have adequate ventilation regardless of the lights used.  You will need a bigger exhaust fan using the HPS, to reduce heat.

HomieHogleg


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## Rosebud (Aug 14, 2011)

I use a t5 for veg now. Much cooler and works as well or almost as well. I leave on 24 hours too. I couldn't do that with the MH. I really like the t5.


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## Hushpuppy (Aug 14, 2011)

Was your HPS open or in a hood? Either way you would have to have some active ventilation to remove heat and bring in fresh air to the plants. I love the T5s but like HH said, they don't have great penetration and 4 bulbs would not be enough to flower well with. I use T5 for clones and veg but then switch to HPS for flower. If you have a hood or cooltube for the HPS, all you have to do is connect a hose from one side to an inline fan that connects to the vent in the ceiling and that will eliminate the heat issue that you had.


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## Locked (Aug 14, 2011)

I use T5's for veg and love them....wldnt use them in flower though. Like it has already been said. They don't penetrate well. Not too mention lumen wise you wld be short I wld think.

HPS in a cool tube or vented hood eliminates most of the heat issues for me.


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## The Hemp Goddess (Aug 14, 2011)

*Ventilation is for more than heat control*.  You need good air exchange regardless of your temps.  Plants need a continual supply of fresh air for proper photosynthesis.  When you are just moving the the air around without exhausting CO2 depleted air out and bringing fresh air in, your plants are going to suffer.  IMO, a minimum requirement for ventilation is exchange of your air every minute.  I personally like to exchange the air 3-4 times a minute.

I veg with T5s and will never go back to MH, however for flowering nothing we have right now is better than HPS.


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## mountain man (Aug 14, 2011)

Hemp Goddess, you need a "stamp" that says that!  I commend you. I cant count how many times i have seen you say this dead-on statement! Make it your signature or something!


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## rebel (Aug 20, 2011)

thg, you have been my Answer to many questions on MP, Thank you.
 so lets do this - my current space 5' long, 7' tall and 16" wide.
 A 4' 4 bulb t5 will fit, and i want seedlings and veg with it.
ok, what type intake fan and exhaust will i need ?

while i have a few in veg, im extending onto my room 8' wide and will use a part of it for the flowering.
 what size 3x3, 4x4 with a 600 hps cooltube ?
fans ?


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## Ruffy (Aug 20, 2011)

read read read rebel, we can help, but not grow for you.:giggle: 
5000lum per sq ft for bud 3000 lum/ft for flower. l x w = sqft:watchplant:


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