Advice on adding another light during flower?

hey guys, im currently entering my 4th week of flower with 4 Sativa clones.
They are all doing magnificently under one 600W HPS light, they've been under that the entirety of the grow even for veg (as the bloke at my hydro shop was trying to save me money).
However I was fucked up during the weekend and ordered another 600W HPS light...

First Question:
Will I be ok to put the secondary light into my grow tent even though im mid flower period or will the extra output likely fuck with my plants?

Second Question:
ive already got one fan through my cool tube plus an intake fan so if I go ahead and put the other cool tube in should I just run a second fan midway through my duct and connect my duct into my carbon filter and extend the ducting. second fan just to make sure I don't lose suction through the added 2m or so of ducting?
Any help would be greatly appreciated, I will take some pictures of the babies now and post a new topic with my progress and where im at.
Thankyou in advance!

How big is your tent?

sorry, 120x120x200cm i thought i put that in there what a rookie

dopeleader said:

hey guys, im currently entering my 4th week of flower with 4 Sativa clones.
They are all doing magnificently under one 600W HPS light, they've been under that the entirety of the grow even for veg (as the bloke at my hydro shop was trying to save me money).
However I was fucked up during the weekend and ordered another 600W HPS light...

First Question:
Will I be ok to put the secondary light into my grow tent even though im mid flower period or will the extra output likely fuck with my plants?

Second Question:
ive already got one fan through my cool tube plus an intake fan so if I go ahead and put the other cool tube in should I just run a second fan midway through my duct and connect my duct into my carbon filter and extend the ducting. second fan just to make sure I don't lose suction through the added 2m or so of ducting?
Any help would be greatly appreciated, I will take some pictures of the babies now and post a new topic with my progress and where im at.
Thankyou in advance!

Click to expand...

Add it. Go big. Or too bad it isn't a MH to increase the THC.

hold up, if i add a MH it will increase THC?
So i would benefit from swapping my new HPS bulb for a MH to run alongside my current HPS?
If that's the case, for the sake of a $40 bulb ill buy a MH lol

OK so after doing some thorough research ive made a decision...
My light just came today, im going to run 2x 600W HPS sidebyside.
only because i cant be fucked trying to find the best way to make sure my MH spectrums are evenly dispersed, because as ive read if i just hang them simultaneously half will get HPS the other half MH and not the regular mix you would get from say a dual spectrum globe

dopeleader said:

hold up, if i add a MH it will increase THC?
So i would benefit from swapping my new HPS bulb for a MH to run alongside my current HPS?
If that's the case, for the sake of a $40 bulb ill buy a MH lol

Click to expand...

Neither MH nor HPS have much if anything to do with adding or subtracting THC content. Vegging plants do best under MH as it is bright light mimicking nature in mid to late spring. HPS is for flowering, it mimics late summer/early fall

My thought was purely on creating a larger yield, i was just asking if the thc part was true or not.
But you answered that well, thankyou.

dopeleader said:

My thought was purely on creating a larger yield, i was just asking if the thc part was true or not.
But you answered that well, thankyou.

Click to expand...

HPS lacks the Blues/Uv part of the spectrum that MH has. So yes, increasing the Uv availability during flower certainly can be beneficial. Want yield, yeah HPS. Search on RM3 and find his journal.

how do I find the journal haha

The size of the garden area will determine the wattage you need. If we assume that the plants will get no sunlight,

a 1000 watt HID light will cover about 7 x 7 feet of growing area.

A 600 watt will cover 6 x 6 feet

a 400 watt will cover 4 x 4 feet, and

a 250 watt will cover 3 x 3 feet.


These sized areas would be considered the “Primary Growing” areas. These lights will light-up larger areas, but plants placed outside of the Primary Growing area, will stretch and bend toward the light; a phenomenon called phototropism. Keep these areas of coverage in mind when using multiple fixtures. The best results occur when the areas of coverage overlap or light movers are used.

I`d add the 2nd light right onto the 1st cool tube

I would not add any fans to your cool tubes

I would use the spare fan you have as an extra in or out fan if things got too hot

I like to bring a 5" or 6" vent into the tent from a low cool source of air then I place it low down in the tent but blowing up at the hot spot, that normally keeps them happy

but if that`s not doing it then I`ll run another extract, does a lot more than trying to suck more through a cooltube as most cool tubes are 125/150mm, you normally struggle with airflow due to the size of the pipe vs the distance it has to travel, so better to run it all in 200mm ducting and cool tubes or just add an in or 2nd extract if it gets too hot

but most of the time its fine

Think the most I saw was 3 x 600 hps in 1mx1m it was hot as fuck but my mate had 12 trees crammed into 15L pots think he was watering 2 times a day by the end of that run....... So he got some leds and then went 3 to 4 led panels with 1 to 2 600 hps per 1x1m tent may have been 1.2m x 1.2m tents

Yeah im working with a 4x4x8 ft tent in rough sizes.
I Had 1 600W light which was doing fine mind you in my garden, however as money is not that much of an issue (im not rich but I do have full-time work so im not relying on growing weed to pay my bills)
So I was going to get a 1000W light and place that inside the tent, Which from what ive read would penetrate deeper into my cavity but would not produce as big of a yield as 2x 600W lights.
I probably don't need the extra light but my 4 plants have COMPLETELY filled my grow area, so I have to push the boundaries of normal practices.
I was stoned, the light was a good idea and I have the fans etc to vent the heat through as they are both cool tubes so it shouldn't get any hotter.
but the result I was hoping for is a better yield, and much more fuller buds.
Thus now the colas that basically touch the sides of my tent get just as much heat/light as the ones that are in the centre of the tent (as my previous light was fixed dead centre.

THE KONASSURE said:

I`d add the 2nd light right onto the 1st cool tube

I would not add any fans to your cool tubes

I would use the spare fan you have as an extra in or out fan if things got too hot

I like to bring a 5" or 6" vent into the tent from a low cool source of air then I place it low down in the tent but blowing up at the hot spot, that normally keeps them happy

but if that`s not doing it then I`ll run another extract, does a lot more than trying to suck more through a cooltube as most cool tubes are 125/150mm, you normally struggle with airflow due to the size of the pipe vs the distance it has to travel, so better to run it all in 200mm ducting and cool tubes or just add an in or 2nd extract if it gets too hot

but most of the time its fine

Think the most I saw was 3 x 600 hps in 1mx1m it was hot as fuck but my mate had 12 trees crammed into 15L pots think he was watering 2 times a day by the end of that run....... So he got some leds and then went 3 to 4 led panels with 1 to 2 600 hps per 1x1m tent may have been 1.2m x 1.2m tents

Click to expand...

My second cooltube will not fit onto the other, as my original cool tube was a touch more expensive.
It is about 800mm long, my new cooltube is only about 500mm once you add ducting to that it ends round 1.8m long.
However ive ducted the new light through from my carbon filter -> first cool tube -> second cool tube -> out top vent with extractor fan and my tent is still trying to suck itself inside itself.
So I don't think I've lost too much power as im using a pretty neat 6'' extractor with some balls.
I also have a 40W oscillating fan on speed 2 that's on 24/7 to deal with any hotspots under the lamps and to blow my colas to bodybuilding proportions.

sounds good mate

What you can do is run one 600 for 2 to 4 weeks before you fire up the 2nd light that way the buds grow in one direction and then putting the 2nd light on makes them spread out more, plus when there small there`s not much plant for the lights to penetrate

I`ve got one set up where I have 1 x 600w and a few leds on 12/12 and a 1000w hps in a cool tube that runs 10/14 , kinda gives the plants a bit of a sunrise/sun set simulation, but the timers got swapped a few weeks ago so the 1000w was coming on 1st but I sorted that, the timers must have got mixed up when we were doing something to them

but not running the 1000w hps for 2 hours less per day actually almost covers all of the power the veg tent uses, so that`s pretty cool

mrgreen2015 said:

The size of the garden area will determine the wattage you need. If we assume that the plants will get no sunlight,

a 1000 watt HID light will cover about 7 x 7 feet of growing area.

A 600 watt will cover 6 x 6 feet

a 400 watt will cover 4 x 4 feet, and

a 250 watt will cover 3 x 3 feet.


These sized areas would be considered the “Primary Growing” areas. These lights will light-up larger areas, but plants placed outside of the Primary Growing area, will stretch and bend toward the light; a phenomenon called phototropism. Keep these areas of coverage in mind when using multiple fixtures. The best results occur when the areas of coverage overlap or light movers are used.

Click to expand...

You are more generous with your light coverage dimensions than most, but it works for me. . My grow area is about 4x6 and a 600w works fine. I rorate my 6 plants as long as feasible, every water (to about week 6 of flower) so they see a bunch light angles.
This grow I kept my 600w MH going tlll the end of stretch ( week 3 of flower) I then switched to a 600w HPS augmented by a 4', 4 bulb t5 holding acombination of blues.

bravedave said:

You are more generous with your light coverage dimensions than most, but it works for me. . My grow area is about 4x6 and a 600w works fine. I rorate my 6 plants as long as feasible, every water (to about week 6 of flower) so they see a bunch light angles.
This grow I kept my 600w MH going tlll the end of stretch ( week 3 of flower) I then switched to a 600w HPS augmented by a 4', 4 bulb t5 holding acombination of blues.
View attachment 3552127

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why do you turn them every week ? what not let one side get big then turn say 4 to 6 weeks into flower ? like just before the plants get too big to turn.... I`ve seen seemorebuds demonstrate the same kinda method but he was just using 1 plant and an led panel he just moved the light instead of the plant

even the larger buds that were faced away from the light seemed to grow some new heads in the direction of the light

I do wonder if its better to turn once a week or just turn the plant half way into flower ?

Guess we need some clones and someone who wants to test out and see lol

Anyway dave that aside some nice looking girls you got there

THE KONASSURE said:

why do you turn them every week ? what not let one side get big then turn say 4 to 6 weeks into flower ? like just before the plants get too big to turn.... I`ve seen seemorebuds demonstrate the same kinda method but he was just using 1 plant and an led panel he just moved the light instead of the plant

even the larger buds that were faced away from the light seemed to grow some new heads in the direction of the light

I do wonder if its better to turn once a week or just turn the plant half way into flower ?

Guess we need some clones and someone who wants to test out and see lol

Anyway dave that aside some nice looking girls you got there

Click to expand...

I turn as often as possible. I start by turning the 1/4 turn a day in veg. Then when they get a little bushy and it's more of a hassle I will move them out and rearrange them depending on which need light the most. Turn the weak side to the light in its time to encourage stronger bud growth.

Or add a second 600W HPS lamp and reduce the need for any rotation XD