Air cooled 400 W HPS - how close top colas t the light in a 4ft tall box?

[desant]

Right i reallise ive been making lots of posts here wiithout searchcing

i did find this:
http://www.icmag.com/ic/showthread.php?t=15558&highlight=close+HPS

but it didnt really answer any of my questions

so i am asking...

400 W air cooled HPS light at 4 ft high from the ground

I reckon it goes like this:

1 ft - soil

1ft veg growth

1 ft flower growth

and 1 ft below the light

All in 4 ft tall box

What do you think

Temps are REALLY low in the box, since it is aircooled

I put my hand 6 inch bellow light and it doesnt get hot that much... feels like your under tropical sun! Caribbean dope fiend and shit lol

So, if i keep it 6 - 12 inch below the light i should be fine?

And 400 hps is bound to get more bud than 250 right? My friend whho i am bulding this grow box for will be delighted!

 

[Jnugg]

Right I realize I've been making lots of posts here without searchcing

I did find this:
http://www.icmag.com/ic/showthread.php?t=15558&highlight=close+HPS

but it didnt really answer any of my questions

so I am asking...

400 W air cooled HPS light at 4 ft high from the ground

I reckon it goes like this:

1 ft - soil

1ft veg growth

1 ft flower growth

and 1 ft below the light

All in 4 ft tall box

What do you think

Temps are REALLY low in the box, since it is aircooled

I put my hand 6 inch bellow light and it doesnt get hot that much... feels like your under tropical sun! Caribbean dope fiend and shit lol

So, if I keep it 6 - 12 inch below the light should I be fine?

And 400 hps is bound to get more bud than 250 right? My friend who I am bulding this grow box for will be delighted!

With a properly cooled air-cooled light 6" -12" from plant canopy is best.Just be sure to check plants for any signs of bleaching or light/sun burn.

Figure 12" for containers,12"-24" for final plany height at harvest (400w HPS can only penetrate about 1.5' 2' max. down into the plants canopy,anything below this level will be loose,airy,popcorn buds and is a waste of time).

Here is a HPS chart to check with:




And a MH chart:

And 400 hps is bound to get more bud than 250 right? My friend who i am bulding this grow box for will be delighted!

Depending on the individual growers experience/expertise...

I might be able to grow more bud with my 400w HPS then you or your buddy with a 250w HPS or vice versa.I may be able to grow more weed with a 250w HPS then your or your buddy can with a 400w HPS.

It takes many things working together in unison or harmony if you will to grow good weed or any amount of good weed like genetics (you can't make a low yielding plant yeild high numbers),light,air/ventilation/cooling,water,nutes etc. etc. and of course last but not least,the knowledge and experience of the grower.


If temps are kept in check,and you start off with good/solid genetics with the right area with plenty of ventilation,a properly air-cooled 400w HPS you can expect anywhere from 0-8oz for a first time grow can be expected.

*NOTE*

I say 0oz. for a first time grow based on little to know growing experince and/or less then ideal/optimal conditions/environment.

I say 8oz for a first time grow based on a lot of growing knowledge and experience with ideal/optimal conditions/environment...or what you could call "dialed-in".

Keep in mind that an 8 oz. harvest is a 1/2 lb. or 224 grams.A decent harvest and it is what you should aim for as a minimum harvest,0.5 gram/watt (1/2 a gram per watt) harvest.

To find GPW,cut all buds when fully ripened and mature,and dry untill smokeable in a joint and the joint stays lit.Weigh your harvest and write down the number in grams.Next / that number by your flowering lights wattage (in your case 400w).

224 grams / 400w = .56 grams per watt.If you are getting less then 200 grams total per harvest per 400w HPS then you are either growing a very low yielding plant or you are doing something wrong.

Getting to the 1 gram per watt mark isn't easy,and takes superior genetics,extreme growing knowledge and experience,and ideal/optimal conditions/environment,so use the 0.5 gram per watt as your starter.

 

[desant]

Wait im confused first u say 6 - 12 inches is enough then 12 - 24 inch???

Also:

"Just be sure to check plants for any signs of bleaching or light/sun burn."

What are the signs of this?

 

[Outportgrower]

Burnt dried leaves. Check for colour. They will tend to turn a light green/white/yellowish if the lights are too close. My experience with a 400 watt is 6" is the closest you want to be with lots of air flow.

 

[Dr Dog]

basically light bleaching looks like there are off colored(burnt) tiles inside the leaf

You can get your plants almost touching the glass of your aircooled.

The closer you get, the better it will be

But the one thing you are forgetting, is that plants will stretch into flower

Some up to 3 times or more.. So your math is right, but can easily be wrong, depending on what your plants want to do

 

[Jnugg]

Wait im confused first u say 6 - 12 inches is enough then 12 - 24 inch?

With a properly cooled air-cooled light 6" -12" from plant canopy is best.12"-24" for final plant height at harvest (400w HPS can only penetrate about 1.5' 2' max. down into the plants canopy,anything below this level will be loose,airy,popcorn buds and is a waste of time).

Again with a properly air-cooled light the light should be kept 6"-12" from the plant canopy.

The 12"-24" was listed as a final plant height at harvest time seeing as a 400w HPS's penetration capabilties (how far below the canopy the light can reach) are no greater than 1'-1.5' and 2' max.

Also:

"Just be sure to check plants for any signs of bleaching or light/sun burn."

What are the signs of this?

You'll know what I am talking about when you see it,if it happens.Bleaching is just what it sounds like,leaves to close to the bulb/reflector will show a lack of chlorophyll and can appear white as if they have been bleached.

Light burnis again exactly what it sounds like.The leaves will appear very dry and brittle,curl and twist and just look ugly and dead.

You can get your plants almost touching the glass of your aircooled.The closer you get, the better it will be...

But the one thing you are forgetting, is that plants will stretch into flower.Some up to 3 times or more.. So your math is right, but can easily be wrong, depending on what your plants want to do

Exactly.

For 100% Indica and Indica dominant hybrids expect the plant to stretch 2-3x the height it was when it was first put into 12/12.

For 100% Sativa or Sativa dominant hybrids expect the plant to finish 3x+ the height it was when it was first put into 12/12.

ie;a 100% Indica or Indica dominat hybrid that is put into 12/12 @ 6" will most likely finish @ 12"-24"....a 100% Sativa or Sativa dominant hybrid that is put into 12/12 @ 6" will most likely finish @ 18"-36"+.

 

[desant]

My experience with a 400 watt is 6" is the closest you want to be with lots of air flow.

Well why did that dude in grow room design forum said i shoudl go with 400 instead of 250 ??? He knew i was growin in 4 x 2 x 2

 

[2fast4u2]

check out my grow in my sig, i grow with a homebox S.

400w mh/hps and when i flower i usually get them pretty close, within a few inches. But they really need to be about 5 inches away from the light so they dont suffer from heat stress.

 

[desant]

This is my buddies second grow

"
You can get your plants almost touching the glass of your aircooled.
"

I thought the rule was - if your hand is ok holding it to the light the plant should be fine too - well i held my hand 6 inches and it felt like a tropical sun! :|



But the one thing you are forgetting, is that plants will stretch into flower

Some up to 3 times or more.. So your math is right, but can easily be wrong, depending on what your plants want to do


Hmmmm my buddie says - hes aiming for DOUBLE grow - grow 1 ft in veg and the train and grow 1 ft max in flower = 2 ft plants

 

[desant]

Jnugg ohhh man i see what u mean

6 - 12 inches to the light when it matures and ready to haarvest

plant lench 12 - 24 inch

got cha

K+

 

[Dr Dog]

This is my buddies second grow

"
You can get your plants almost touching the glass of your aircooled.
"

I thought the rule was - if your hand is ok holding it to the light the plant should be fine too - well i held my hand 6 inches and it felt like a tropical sun! :|



But the one thing you are forgetting, is that plants will stretch into flower

Some up to 3 times or more.. So your math is right, but can easily be wrong, depending on what your plants want to do


Hmmmm my buddie says - hes aiming for DOUBLE grow - grow 1 ft in veg and the train and grow 1 ft max in flower = 2 ft plants

OK

But you dont decide how much they stretch, the plants do, and they will surprise you how fast they grow..just be prepared, maybe less plants at first, to see if you need to do some training

Well I am not sure what your idea of tropical sun is, you should get a thermometer at your canopy to see your temps there. Less that 80f is ideal, 76 is perfect but under 80 you will not see any issues

 

[desant]

"But you dont decide how much they stretch"

even with tying/training stem branches?

:|

 

[DiscoBiscuit]

Training doesn't stop growth, just makes it more manageable.

 

[Jnugg]

OK

But you dont decide how much they stretch, the plants do, and they will surprise you how fast they grow..just be prepared, maybe less plants at first, to see if you need to do some training

Well I am not sure what your idea of tropical sun is, you should get a thermometer at your canopy to see your temps there. Less that 80f is ideal, 76 is perfect but under 80 you will not see any issues

Just what I was going to say,you have no control overhow much they are going to stretch,you can combat it with techniques like Low Stress Training or doing a Screen of Green.

Ideal air temperature at Canopy level is 70-78F with 75f being aboslute best IMO.Lights off your air temps at canopy level should be 5f-10f lower or 65f-68f but low 70's is fine.Once you get over 80f you'll start running into problems and have a negative impact on over growth and yeild.Once you are into the 85f-90f air temperature at canopy level is when you would add Co2 but I am not sure if that's even worth it,I'd rather keep temps 75f-78f.


What will you be doing for ventilation and air-cooling of the light.The only two types of fans that are proven to get the job done are Inline Centrifugal Fans (Vortex,Can Fan,Eco Plus,Elicent) and Mixed Vent Fans (Soler & Palau),especially if using a carbon filter to deodorize the hot smell exhuast air.

I would recommend a 4" 172cfm Inline Centrifugal or a 6" S&P TD-150 for air-cooling the 400w HPS.

for ventilation...your area is 2' x 2' x 4' = 16 cubic feet

16 cubic feet x 3 =

For ventilation I'd recommend eithe a 4" 172cfm Inline Centrifugal or a 5" S&P TD-125 and a Can 33 carbon filter.


Now if you want to use one fan to both ventilate the grow while deodorizing the stinky air and air-cool the 400w HPS I would recommend a 6" 392cfm-440cfm Inline Centrifugal or the 8" S&P TD-200 and a Can 50 or Can 75 carbon filter.

 

[desant]

Jnugg those charts are great thanx a lot man!

 

[desant]

dude, i already got a great fan, works really good

http://www.icmag.com/ic/showthread.php?t=141395

 

[Jnugg]

dude, i already got a great fan, works really good

http://www.icmag.com/ic/showthread.php?t=141395

That's good and all but you fail to mention the size of the fan and what it pushes as far as airflow/cfm.

For all I know it's a 4" Inline Centrifugal or a 12" Inline Centrifugal that pushes anywhere from 150cfm-1200cfm.

Need specifics....

 

[desant]

ohhh right, let me get my figures

its a 125mm German 250m3/hour heavy duty fan, its really strong and works really well..

But im not sure if i can run it 24/7... and i might need a speed control device since its a bit loud...

 

[Jnugg]

ohhh right, let me get my figures

its a 125mm German 250m3/hour heavy duty fan, its really strong and works really well..

But im not sure if i can run it 24/7... and i might need a speed control device since its a bit loud...

125mm = 4" and 250m3/hour equates to 150cfm so you have a 4" 150cfm inline centrifugal.

Given little to no duct losses from static pressure and that fan should keep you 6-10f above ambient temps.

Ambient air temperature is the air temperature of the air in the room your grow box/cab/tent will be sitting in and drawing esh air from,so if your ambient temps are 72f your air temps in the cab should run 78f-82f.


Why don't you know if you'll be able to run the fan 24 hours a day 7 days a week?

Some things you can do to reduce the noise of the fan itself and the noise of the air moving through the ducting and exiting the ducting:

1)Build an insulated fan box constructed from 3/4" MDF (medium density fiberboard) and line the insides with some form of acoustical foam.This will reduce the noise made by the fan/fans motor.

2)Use oversized insulated ducting.I say oversized so that air is allowed to move more freely therefore for a 4" fan you would use 6" insulated ducting.I say insulated ducting becuase that not only keeps the hot exhuast air from radiating out of the ducting and also becuase it will reduce the noise of the air moving around within the ducting.

3)Build a DIY duct muffler or buy one.Attach at the end or near the end of your exhuast duct run.This will reduce the noise of the air exiting the exhuast ducting and does not add static pressures so there are no lossses or reductions in airflow/cfm.

4)Attach a carbon filter either inside the grow so that the fan is pulling the stinky air through the filter or outside the grow so that the fan is pushing the stinky air into the filter.Carbon filters add static pressures.....

Static pressure/duct losses can be caused by many things like too small ducting,duct reducers/y splitters,90 degree bends in ducting runs,long runs of ducting etc.


Make sure the shortest run of ducting is on the inlet side of the fan or the side of that fan that sucks air in,and make sure the longest run of ducting goes on the exhuast side of the fan or the side that blows air out.If using passive intake vents to create a negative pressure environment (as long as exhuast fan runs 24/7 into the carbon filter no stinky air will escape,hence negative pressure environment) make sure tha the area of the intake vent is atleast 2-3x the area of the exhuast fan...ie;a 4" fan has 12.56 sq. inches of area so we need 25.12-37.68 sq. inches of intake area as a minimum,but more will not hurt.

Once you slap a carbon filter on there though you will be experiencing static pressure which will cause a loss or reduction in the fans airflow/cfm....how much static pressure depends on the carbone filter you match to the fan.

By adding a carbon filter to that fan I would expect cab temps to be 10f-15f+ above ambients so if ambient temps are 72 expect cab temps to be 82f-87f.You can aleviate those high temps by keeping ambinet temps 65f-67f so cab temps would sit at 75f-82f....or you could replace the 4" 150cfm fan with a 6" 350cfm-440cfm inline centrifugal and run that on a solid state speed controller at 50%-75% and keep cab temps 2f-5f above ambient,so if ambient temps were 70 cab temps would sit at 72f-75f.

 

[FreezerBoy]

Dude, you NEED to do some homework. All of your questions are on a pre kindergarten level and indicate you have NOT done your reading. You're asking US to do YOUR work. If you won't hold up your end, why should we?

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