What size light?

I wanna set up a grow box with 3 plants..

What size light should i use?

And is it best to use MH lights for veg stage and HPS for flowering?

if you can keep it cool id go 400w get a switchable one so you can use a mh bulb for veg and hps for budding.

Cool thanks. thats what i was thinking... I've got 2 exhaust fans up top and 2 intake fans at the bottom of the grow box so should be fine with cooling... the box is also mylar lined so light should be good all over.

400 W would be plenty - don´t need a switchable ballast , MH work fine in a HPS ballast.

mh is pointless besides using it for extra lighting and i know the blue spectrum is "better" for veg but if you veg a plant under hps it will be stronger, mh costs more and lasts half as long. of that size grow i would go with 600w

SmokeNeth said:

I wanna set up a grow box with 3 plants..

What size light should i use?

And is it best to use MH lights for veg stage and HPS for flowering?

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Depend on the size of the box you are going to setup or buy.You can use anything froma 150 hps to a 1000 watt.I prefer to use hps all thru or use floros/t5s to veg.I have a mh conversion bulb but like said hps is more efficient than its counterpart mh.

Box is 4ftH x 2ftW x 2ftD.

Its going in my workshop disguised as a tool cupboard so cant be too big.

So HPS works fine for veg stage? Would a cheap fluoro or 2 help the veg stage along too or just go HPS?

SmokeNeth said:

Box is 4ftH x 2ftW x 2ftD.

Its going in my workshop disguised as a tool cupboard so cant be too big.

So HPS works fine for veg stage? Would a cheap fluoro or 2 help the veg stage along too or just go HPS?

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Yes it would help.Yes hps works fine for veg.
For that size if you have exhaust down to a t then go with a 250 or 150.A 400 seems a bit much for that size but if you have the money to invest to make sure heat will not be a problem then go for it.

Well i have 2 x 120mm intake fans at the bottom and 2 x 200mm exhaust fans on the top going through a carbon filter. I can always add more fans if need be.

Also i think you would need a cooltube or aircooled reflector in a small space it would put off alot of heat but it can be done.

Not sure if i understand... The aircooled reflector or cooltube... are they to keep the temp down? But they give off heat themselves?

My box is fully lined with Mylar so the light spread shouldn't be an issue......

SmokeNeth said:

Not sure if i understand... The aircooled reflector or cooltube... are they to keep the temp down? But they give off heat themselves?

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It takes the heat caused by the light and exhaust it out the room..

oh cool.. so on a cooltube do i put a fan/exhaust on the end off tube to extract heat?

sorry for all questions. Just wanna get the grow box right before i start growing

use 3 23 watt cfls along with 1 32 watt cfl! it does the job!

SmokeNeth said:

oh cool.. so on a cooltube do i put a fan/exhaust on the end off tube to extract heat?

sorry for all questions. Just wanna get the grow box right before i start growing

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Use ducting at the end of the duct hose you put your extractor fan.It should be pulling the hot air out..

Thanks for the advice wyteberry.

I'll post pics once i start growing!

dude i have a 2x2x4 box as well same size as yours i use a 400w hps works real nice for it i have a non cooled hood but i have a 80cfm bath fan hooked up right at the top by the light with my door close it stays at 85f degrees

SmokeNeth said:

Thanks for the advice wyteberry.

I'll post pics once i start growing!

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No problem.Ill be glad to see how you do this.