Lighting my grow cab, is this setup ideal?

[Brucefx]

Hi guys I'm currently planning a cabinet grow, my grow room measures 4x2.5x2.5 (hxwxd feet)

I can't decide between cfls or hps, what do you think of this setup for my grow cab

MH + HPS Hydroponic 250W Grow Light Kit Ballast Euro Reflector 250 watt Bulb | eBay

Is this ideal?

Will heat be a problem in my space? How much ventilation will I need? Thanks

 

[Fuzzy Duck]

Mmm height of growing area appears to be the issue once you factor in plant pots size, reflector size, distance of light to prevent burn if using HPS & strain grown !

On average ya more likely have aprox of 2.5 foot of total growth height which also factors in stretch once in flowering !


I would suggest using an air cooled hood if using 250w HPS flowering, 250w MH for vegging, an air cooled hood will help reduce over all temps in the growing area and allow for some extra growth space with out suffering with burn issues from a standard hood...

The other option is CFLs which ideally need to be kept aprox 2.5 cm to 5 cms from plant growing tip as cfls suffer greatly from the square law of light effect over distance.

HPS will always yield greater than when compared to cfls tho...


Other factors to considor are strains growth height & dominate genetics this effects over all height of plant grown & would be more inclined to grow an indica dominate strain due to their shorter growing nature when compared to sativa strains


Ya need to shop around for short growing strains tho & i may even suggest auto flowering strains as they normally have shorter growing height !

Ultimately grow style can be used to control height also, such as SOG lots of little plants & you may get away with between 9 to 20 plants in your space, works best if ya got a mother plant to provide clones tho & once clones are rooted veg for 2 weeks before flipping lights to flowering cycle of 12/12... more likely looking at using 2 litre pots for that.

Scrog is another alternative via training the plant by super cropping techinques such as topping, LST & eventually training throught a wire mesh grid so ya get loads of cola bearing bud sites, this method can provide good yields beyond the normal.



Anyway ya gonna need 4" inline fan to provide suitable ventilation with a 250w hps/mh in that space with current choice of bulb and reflector.

 

[Brucefx]

Mmm height of growing area appears to be the issue once you factor in plant pots size, reflector size, distance of light to prevent burn if using HPS & strain grown !

On average ya more likely have aprox of 2.5 foot of total growth height which also factors in stretch once in flowering !


I would suggest using an air cooled hood if using 250w HPS flowering, 250w MH for vegging, an air cooled hood will help reduce over all temps in the growing area and allow for some extra growth space with out suffering with burn issues from a standard hood...

The other option is CFLs which ideally need to be kept aprox 2.5 cm to 5 cms from plant growing tip as cfls suffer greatly from the square law of light effect over distance.

HPS will always yield greater than when compared to cfls tho...


Other factors to considor are strains growth height & dominate genetics this effects over all height of plant grown & would be more inclined to grow an indica dominate strain due to their shorter growing nature when compared to sativa strains


Ya need to shop around for short growing strains tho & i may even suggest auto flowering strains as they normally have shorter growing height !

Ultimately grow style can be used to control height also, such as SOG lots of little plants & you may get away with between 9 to 20 plants in your space, works best if ya got a mother plant to provide clones tho & once clones are rooted veg for 2 weeks before flipping lights to flowering cycle of 12/12... more likely looking at using 2 litre pots for that.

Scrog is another alternative via training the plant by super cropping techinques such as topping, LST & eventually training throught a wire mesh grid so ya get loads of cola bearing bud sites, this method can provide good yields beyond the normal.



Anyway ya gonna need 4" inline fan to provide suitable ventilation with a 250w hps/mh in that space with current choice of bulb and reflector.

Thanks a lot for you informative reply! I should have gone into more detail in my first post, I apologise for that, I do plan to scrog in there, maybe even u shaped scrog for more net square footage?

And also I'm going to grow in a nft gt 205 (NFT GT205 250w Starter Kit - GreenSea Hydroponics) as its only 7 inch high, I researched for hours for what medium to grow in and the height of this tipped the decision in favour this way!

Do you think the light setup I'm thinking of will be enough? That 250 hps throws out 32000 lumens I think which should give me just over 5000 per foot in that cab, is that ideal or just passable? And also I'm undecided as to wether to use a duel spectrum hps or to use the mh veg and hps flower, what will the plants like more do you think?

And also is the air cooled hood a necessity? I'm trying to keep cost down and have no idea exactly how hot hps will be in my cab!

Sorry for all the questions I'm just trying to learn as much as possible and get this right!

Thanks

 

[Fuzzy Duck]

250w bulb whether hps/mh or the newer dual spec is quite optimal for ya space

Air cooled hood is optimal if ya can afford... but even with a normal reflector ya should get away with a 6" to 8" inch hanging height safely with a 250w bulb & may increase height if using a MH !

For some techinical reason beyond my own mortal understanding MH burn hotter than HPS, ya may notice a slight increase in temps if ya go down that route between the two bulbs types


I have seen a couple of grow journals here on 420 who have used dual spectrum HPS/HID bulbs for both veg & flowering with perfectly good results & i have no reason to disbelieve


After all i use a dual spec bulb by grolux (400w) for flowering only, with pretty good results for a soil grower using a organic method with a tad bit of super cropping involved !

I would use the 400w dual spec for vegging tho if budget allowed in real life, but prefer a gaint cfl of 125w 6400k/kelvin for vegging as its cheaper to run... mildly slower growth rate but works out nicely with my perpetual grow style of a harvest every 2 months !

I'm a little tight fisted when it comes to paying the the old electric bill, but maintian a stance on growing weed as cheaply as possible with max results as best as i can !


I would still be incline to use a 4" inline fan for an exhaust to control temps coupled with a passive vent based at the bottom of the tent tho to control temps...

 

[Brucefx]

Thanks good to hear thanks fuzzyduck. You got do what works for you, if the 125 cfl works with your plan then that's got be the way to go!

Any advice on how I can vent this thing, I'm thinking of creating a negative pressure environment with passive intake, but I'm struggling with how much exhaust ventilation I'm going to require, I must have read a hundred different opinions on the subject! I could do with seeing something as I'm struggling to picture what I'm aiming to build, filter pipe fan, fan sits on side of box or blows into black PVC elbow etc?

Also in a negative pressure environment do you need to keep fan and filtration on at all times as, if they are rigged up with the lights when the lights switch off so does the fan and I'm guessing smelly air is going to seep out of passive intake holes?

thanks again!

 

[Fuzzy Duck]

I can not remember the whole negative pressure stuff at present... but its like suckiing the air out of a bag.


So in a inclosed enviroment you will require 2 fans, 1 being extraction & the other fan being intake... the extraction fan is normally the larger one as in volume of air which can be moved per hour, intake a smaller volume of air.

E.g 5" fan extraction, 4" fan intake for an example, you can shop around & find dual speed fans which wolfnado fans spring to mine if they are aviable in your country... fan speed controller can also be purchased some help maintain temp/humidity also but come at greater cost.



Most people use a passive vent based at the bottom of grow tent/space & a extraction/exhaust fan at top of grow tent/space as warm air rise's... the extraction fans pulls new fresh in air through the passive vent & so forth. ( No negative pressure involved )



Its a wise idea to leave exhaust fan running 24/7 as lights off/dark period creates a humidity spike... high humidity of 70% over a prolonged time can induce powdery mildew & bud rot problems 80% humidity is the real danger level., this may all depend on where you live in the world tho as humidity changes between different terrians/places on earth effecting our own growing enviroments.



Heres some pic's of my own grow tent...

Carbon filter & exhaust fan always placed at the top of the tent or growing area as warm rise's & thats the stuff ya want to extract to control ya temps

The model of tent used comes with passive venting & velcro flaps, i just open one of these up to act as passive intake.

My own temps normally sit around 26c to 27c most of the time, even with the passive vent odour is minimum if the filter & fan is left to run 24/7... but must say carbon filters do not remove 100% of the smell & some times smelly gels/blocks etc may need to be used.

Odour is at its peak in flowering tho with some strains being more smelly than others & this may include vegitive phase also

 

[goathead]

All I can say "Fuzzy" is I am glad to have made your acquaintance. I really appreciate your forthwright answers. Reminds me that I still have so much to think about and learn. i will get there some day.... thanks "Bruce" for asking the question. i get task oriented and forget to be solution oriented.

 

[GreatLife4All]

Just to add a small thing to what Fuzzy Duck said...

Warm air retains more moisture than cold air. By placing the exhaust at the top of the tent - you are definitely pulling out the warm air, but in addition you are pulling out all the moist air. This helps to keep the humidity in check - which will be critical for your small space.