watt lights 2 use?

[hellbilly]

i am wanting to grow in my attic,and i am a little confused as to the lihgting.i want to use a 430 watt son agro.the problem is the height of my attic.the space is 5' x5'.it is 2' 8" at it's lowest height & 4' at it's highest.is the 430 watt to much light? i am worried it will be too close to my plants and burn them.i would really apprec. some input from you guys!

 

[Ekoostik_Hookah]

never heard of the 430

 

[hellbilly]

hookah: it actually works with a4oo watt ballast.it's an hps but has added light in the blue spectrum[or so i've read].thus making it a430 watt bulb.the bulb is called sonagro and i think it's made by phillips? any thoughts to this or how i can light the above mentioned space?any input is greatly appreciated!

 

[Lil Elvis]

Hello Hellbilly,

I think you are fine. In a perfect world where all you have to do is worry about the garden and not someone else finding your garden...50w per square foot is a minimum rule and 100w per square foot is the max (just a waste after that) for optimal efficiency. I have grown at 37w per sqft and did fine.

You have an area of 25sqft so you have no worries about hitting the max. The only thing I could think about would be the penetration to the lower part of the plant. You might see one or two leaves turn yellow down there but with a max height of 4ft…that should not be an issue.

I am not aware of any "volumetric" rule of thumb for light guides; only in area. Be sure and do the hand test between the top of the plants and the light and you should do great. If you don’t have one already, a 6" clip-on fan blowing between the light and the top of the plants (canopy) would help if you experience burning.

Good growing…

Lil Elvis

 

[hellbilly]

thanx lilelvis.i will keep you posted w/my room progress.

 

[md.apothecary]

be cautious!! that wattage will put out heat and you won't be able to raise it too much if 4ft is your max height! Plan on using a SCROG or LST along with your growing

you'll need room for raising your light from the tops of your plants.

 

[Hick]

Hello Hellbilly,

The only thing I could think about would be the penetration to the lower part of the plant. You might see one or two leaves turn yellow down there but with a max height of 4ft…that should not be an issue.

I am not aware of any "volumetric" rule of thumb for light guides; only in area.

Good growing…

Lil Elvis

It's called the "The Inverse Square" Law... http://csep10.phys.utk.edu/astr162/lect/light/intensity.html

The intensity of light observed from a source of constant intrinsic luminosity falls off as the square of the distance from the object. This is known as the inverse square law for light intensity.

The inverse square law for intensity
Thus, if I double the distance to a light source the observed intensity is decreased to (1/2)2 = 1/4 of its original value. Generally, the ratio of intensities at distances d1 and d2 are

 

[hellbilly]

well...i wonder if a 250watt hps w/flouros 4 sideliting would be better..any thoughts?

 

[hellbilly]

ok md i know the what the scrog is[ but first i need fems] but what is LST?and could you give me abrief tutorial?i also read i could put apiece of glass below the bulb to deter heat?

 

[Hick]

ok md i know the what the scrog is[ but first i need fems] but what is LST?and could you give me abrief tutorial?i also read i could put apiece of glass below the bulb to deter heat?

..Might try thr "search" function at the top of the page. Search "Low stress training".
Tempered glass will work, but ordinary window glass can't take the heat.

 

[md.apothecary]

you can move heat with fans, glass, force cooled lights, etc. but the heat still has to go somewhere. Displacing heat is okay, but the best thing to do is minimize it from the get go. This is a LOT harder than it sounds of course...

LST is a tie down method to create larger branches, etc. It's got quite a good amount of coverage in the forums, just check around or search. However... in my particular situation, I have a CFL flower section now that I am quite happy with at the moment. The temps are in the 70's! With a 400w HPS I was in the 100's with out a problem, and my grow area is a 1.25ft x 3.25ft x 6ft area. WITH passive intake holes and fans at the top exhausting air. No force cooled reflectors or anything fancy like that.

There just wasn't a way for me to do HID lighting in this area without spending more money on ventilation, etc.

 

[goddog]

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[jash]

i am wanting to grow in my attic,and i am a little confused as to the lihgting.i want to use a 430 watt son agro.the problem is the height of my attic.the space is 5' x5'.it is 2' 8" at it's lowest height & 4' at it's highest.is the 430 watt to much light? i am worried it will be too close to my plants and burn them.i would really apprec. some input from you guys!

im using the same bulb its an 425w philips son agro in a space 3'.4'' x 2 x 5'.8''height- during the winter the heat is ok (72-82 during light) but in the summer goes to mid 90's sometimes. i think you could use that bulb in your space if you can provide good ventilation and at least a hood with a glass if not an air cooled plus LST for your plants

 

[hellbilly]

thanx guys. alot 2 consider.i will keep ya'll posted as to what i come up with but lst[ i researched it a little] sounds like the best thing along w/ good ventilation.my mouth is watering in anticipation of harvest time ..lol .