First real grow in 2x4 tent unsure on Promix Hp and more

Hey guys, so this is my first real grow apart from years ago with a friend of mine, but that's besides the point.


So I've recently ordered myself a 2x4 tent and 600w dimmable HPS/MH kit and plan on sticking this in the closet. I'll be running a 6" inline fan and carbon filter/scrubber vented to the closet. I haven't bought the fan or filter yet as I'm wondering recommendations on some of the quieter ones that can easily push the stink out of my 2x4. I've heard a 6" running at a lower speed is still quieter than a 4" running at full tilt. If sound is an issue I can put in a silencer.

Now my biggest issue I'm having right now is soil. The seeds have been germed and placed in soil yesterday. I ended up buying the Promix HP as it was the only soil I could find without slow release nutrients in it. As this is a soilless mix, I will have to add nutrients sometime around the first week of growth. Any recommendations on nutrients made for a soilless grow? Should I mix worm castings or anything else to the soil before mixing into the final pot? Or should I just go with a regular feeding schedule?

Hashishh said:

Hey guys, so this is my first real grow apart from years ago with a friend of mine, but that's besides the point.


So I've recently ordered myself a 2x4 tent and 600w dimmable HPS/MH kit and plan on sticking this in the closet. I'll be running a 6" inline fan and carbon filter/scrubber vented to the closet. I haven't bought the fan or filter yet as I'm wondering recommendations on some of the quieter ones that can easily push the stink out of my 2x4. I've heard a 6" running at a lower speed is still quieter than a 4" running at full tilt. If sound is an issue I can put in a silencer.

Now my biggest issue I'm having right now is soil. The seeds have been germed and placed in soil yesterday. I ended up buying the Promix HP as it was the only soil I could find without slow release nutrients in it. As this is a soilless mix, I will have to add nutrients sometime around the first week of growth. Any recommendations on nutrients made for a soilless grow? Should I mix worm castings or anything else to the soil before mixing into the final pot? Or should I just go with a regular feeding schedule?

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so how do you plan to run the 600 in a hood with air cooling? Ive ran a 600 in a 2x4 genetic test tent and you have to turn the reflector hood/light sideways so air cooled hood will fit. This cause alot of shadowing and really limits the light being used correctly.

Fan wise yes a 6inch on controller is quieter then 4inch. I prefer Vortex fans and will only use Phresh brand carbon filters.

Can you buy Fox Farm Ocean Forest? if so mix it with the HP at different ratios based on plants life cycle. so 1 part FFOF to 4 parts Hp for seedlings, FFOF 1:3 Hp ratio in early veg, 1:2 veg, and 1:1 in final bloom pots. those numbers you can adjust as you figure out your method.

booms111 said:

so how do you plan to run the 600 in a hood with air cooling? Ive ran a 600 in a 2x4 genetic test tent and you have to turn the reflector hood/light sideways so air cooled hood will fit. This cause alot of shadowing and really limits the light being used correctly.

Fan wise yes a 6inch on controller is quieter then 4inch. I prefer Vortex fans and will only use Phresh brand carbon filters.

Can you buy Fox Farm Ocean Forest? if so mix it with the HP at different ratios based on plants life cycle. so 1 part FFOF to 4 parts Hp for seedlings, FFOF 1:3 Hp ratio in early veg, 1:2 veg, and 1:1 in final bloom pots. those numbers you can adjust as you figure out your method.

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The hood I purchased is only 2 feet long so that gives me 2 feet to run my fan/filter meaning it will be tight. I will know more on the placement on Monday when the tent arrives (was supposed to be here Thursday).

I've been looking at the vortex fans, are they really as quiet as people tout them to be? As far as filter I wasn't planning on cheaping out as smell, noise and heat are my main concern at the moment, which brings me to my next question:
How hot will a 600w HPS get in a 2x4 being vented into a 3x10 closet? I was thinking of running a portable ac from my window into the bedroom to keep room temps down and keep a constant flow of fresh air in and out of the tent. Would I be fine just running passive intake and the fan/light/filter as outtake directly into the closet?
I had been planning on hooking everything up and running it for a couple days before placing the early seedlings in the tent to monitor heat and humidity and make adjustments as needed. Currently they are sitting on the windowsill waiting to sprout.

Unfortunately, being Canadian, fox farms soil is unavailable to me or I would have went with that in the first place. I do believe I am able to get a hold of their fertilizers if I'm not mistaken.
On the bright side, being Canadian means I will be legally allowed to cultivate up to 4 marijuana plants in my household, which will be right around when I harvest in October.

Edit: Just for the record the full 600w may not even be needed as I'm currently only sprouting 2 Granddaddy by Native Seed Co and have plans to take the healthiest and scrog it to its fullest potential.

Your Pro Mix is fine. Treat like hydro and feed every time. Your nutes should have a feeding schedule for seedlings and cuttings. Go light if in doubt.

Cooling will be a huge issue. Get plenty of air moving at all times including lights out.

Hashishh said:

The hood I purchased is only 2 feet long so that gives me 2 feet to run my fan/filter meaning it will be tight. I will know more on the placement on Monday when the tent arrives (was supposed to be here Thursday).

I've been looking at the vortex fans, are they really as quiet as people tout them to be? As far as filter I wasn't planning on cheaping out as smell, noise and heat are my main concern at the moment, which brings me to my next question:
How hot will a 600w HPS get in a 2x4 being vented into a 3x10 closet? I was thinking of running a portable ac from my window into the bedroom to keep room temps down and keep a constant flow of fresh air in and out of the tent. Would I be fine just running passive intake and the fan/light/filter as outtake directly into the closet?
I had been planning on hooking everything up and running it for a couple days before placing the early seedlings in the tent to monitor heat and humidity and make adjustments as needed. Currently they are sitting on the windowsill waiting to sprout.

Unfortunately, being Canadian, fox farms soil is unavailable to me or I would have went with that in the first place. I do believe I am able to get a hold of their fertilizers if I'm not mistaken.
On the bright side, being Canadian means I will be legally allowed to cultivate up to 4 marijuana plants in my household, which will be right around when I harvest in October.

Edit: Just for the record the full 600w may not even be needed as I'm currently only sprouting 2 Granddaddy by Native Seed Co and have plans to take the healthiest and scrog it to its fullest potential.

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See with a 2ft hood you will have to turn it sideways to hook up exhaust which means most light will be reflected into walls and dark ends of bulb will not shine enough light to hit outer 1ft on each end of tent.

Temp wise it all depends on ambient temperatures that are getting sucked into tent. Keep them low and will have no issues with heat, plants can almost touch 600 if temps are good.

By the way the mycchoriza in the Pro Mix need to eat. Feed unsulphured molasses. 1-2 tsps in a gallon of water or with your feed

hotrodharley said:

Your Pro Mix is fine. Treat like hydro and feed every time. Your nutes should have a feeding schedule for seedlings and cuttings. Go light if in doubt.

Cooling will be a huge issue. Get plenty of air moving at all times including lights out.

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My only issue with daily feedings is inexperience and the fact I often get sent out of town overnight for work and due to this the wife will have to water while I'm gone and she doesnt have a green thumb what so ever. Fans and filter will be going 24/7 once flowering kicks in. I believe a desk fan should be enough to keep them cool and keep air moving during the night while in veg, but please correct me if I'm wrong.

Oh and as far as the molasses go, I believe someone told me this years ago, thanks for the tip! I'll feed with molasses the next watering I give them to keep the mycorrhizae happy.

booms111 said:

See with a 2ft hood you will have to turn it sideways to hook up exhaust which means most light will be reflected into walls and dark ends of bulb will not shine enough light to hit outer 1ft on each end of tent.

Temp wise it all depends on ambient temperatures that are getting sucked into tent. Keep them low and will have no issues with heat, plants can almost touch 600 if temps are good.

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Hmm I see what you're saying now. I suppose I will have to cross that bridge when it comes and adjust as necessary. How about locating the filter on the top of the tent inside and running ducting? I will have to see what the space looks like once it comes in. So I should be fine with an ac capable of keeping temps down in the bedroom then?

Hashishh said:

My only issue with daily feedings is inexperience and the fact I often get sent out of town overnight for work and due to this the wife will have to water while I'm gone and she doesnt have a green thumb what so ever. Fans and filter will be going 24/7 once flowering kicks in. I believe a desk fan should be enough to keep them cool and keep air moving during the night while in veg, but please correct me if I'm wrong.

Oh and as far as the molasses go, I believe someone told me this years ago, thanks for the tip! I'll feed with molasses the next watering I give them to keep the mycorrhizae happy.



Hmm I see what you're saying now. I suppose I will have to cross that bridge when it comes and adjust as necessary. How about locating the filter on the top of the tent inside and running ducting? I will have to see what the space looks like once it comes in. So I should be fine with an ac capable of keeping temps down in the bedroom then?

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if bedroom temps stay in low 70s you will have no issues

booms111 said:

if bedroom temps stay in low 70s you will have no issues

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Exactly. No daily anything involving water. Be sure to let the medium dry a bit before feeding each time. Overwatering kills more plants than all other causes combined.

Lets go back to the basics. A 600w HPS in a 4x2 is going to warm up fast and yes it all has to do with ambient temps.
But your talking about venting it into the room its in, which isn't really a room and itself is a small space.
What is going to happen is the air will pass through your tent at whatever rate, its going to warm up, your then going to recycle that air because your not venting out of the house, its going to warm up some more and some more and it will continue until temps are sky high.
You could use a 10" fan and have it like a wind tunnel and it wouldn't make any difference because the air in that closet cant cool down quick enough. It also will deplete in co2 since there is no real air exchange going on.

Find a way to vent that heat out of the house!

coreywebster said:

Lets go back to the basics. A 600w HPS in a 4x2 is going to warm up fast and yes it all has to do with ambient temps.
But your talking about venting it into the room its in, which isn't really a room and itself is a small space.
What is going to happen is the air will pass through your tent at whatever rate, its going to warm up, your then going to recycle that air because your not venting out of the house, its going to warm up some more and some more and it will continue until temps are sky high.
You could use a 10" fan and have it like a wind tunnel and it wouldn't make any difference because the air in that closet cant cool down quick enough. It also will deplete in co2 since there is no real air exchange going on.

Find a way to vent that heat out of the house!

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Room is only 110 sq ft so I decided to get a window AC. Should mask some of the noise from the fans as well, as discretion is key for the time being. If 600w is too hot I can always drop it down to 400w.

Have a 6 inch cloudline t6 fan and IPower 6 inch carbon filter coming as well. They should be here any day. Then I can mess about trying to figure out how to rig up the ventilation and lights in this small space. Any recommendations?

Hashishh said:

Room is only 110 sq ft so I decided to get a window AC. Should mask some of the noise from the fans as well, as discretion is key for the time being. If 600w is too hot I can always drop it down to 400w.

Have a 6 inch cloudline t6 fan and IPower 6 inch carbon filter coming as well. They should be here any day. Then I can mess about trying to figure out how to rig up the ventilation and lights in this small space. Any recommendations?

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Yeah I would dim it down to 400w. There's literally no need for 600w in a 2x4, you wouldn't see much benefit.
If you dim it then use a 400w bulb, don't dim a 600w, it changes the spectrum and burns bulbs out, something they often fail to tell you when buying digital dimmable ballasts!

As far as ventilation goes, Fan and filter at the top, offset with passive intake vents open at the bottom, all top duct socks closed bar the one used for extraction. Thermometer above the light line (shaded from direct light) in well circulated air.
A couple of circulation fans running where you can fit them without losing floor space.

coreywebster said:

Yeah I would dim it down to 400w. There's literally no need for 600w in a 2x4, you wouldn't see much benefit.
If you dim it then use a 400w bulb, don't dim a 600w, it changes the spectrum and burns bulbs out, something they often fail to tell you when buying digital dimmable ballasts!

As far as ventilation goes, Fan and filter at the top, offset with passive intake vents open at the bottom, all top duct socks closed bar the one used for extraction. Thermometer above the light line (shaded from direct light) in well circulated air.
A couple of circulation fans running where you can fit them without losing floor space.

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I'd never heard that regarding the bulbs. If the spectrum is affected wouldn't growth as well? Currently I'm just using a crappy 600w bulb from Amazon so if there's no risk of burning out the ballast itself or hindering plant growth I may just stick with that bulb until I can decide on which to go with next.

Originally I had been planning on going fan - light - filter - out but I'm worried on noise created with the fan being open on one end and have read these fans are much more effective when used to pull air rather than push (I was originally Thinking blowing air on the lights would cool them down faster/more effectively but I'm not so sure the set up is a great idea regardless). I'll try and play around and see if I can get what you mentioned to work.

Will be buying a hygrometer or two today (one in the tent and one outside to monitor ambient temps of the closet), and a couple small clip on desk fans.

Now I don't know if I'm overthinking but if ambient temp in the room is currently 65-70f with ac going, how much hotter should I expect the room and tent to rise with a 400w hps going come flower?

Oh and on another note the next step for me is to build a SCROG screen so that will be interesting! Ill post pics this coming Friday of the whole set up and see what you guys think.

The temp rise from ambient will depend on how much your AC can keep up with cooling the room when the lights are on and how much the air has to be exchanged to keep temps in range within the tent itself. Its something I don't have a formula for unfortunately. Except to say 1watt is 3.41 btu per hour.
You will have to set up and try it out.

If its an air cooled light then filter>light>fan>duct out of tent. That would probably be the only way to set it up given the dimensions of the tent. Unless its an inline filter and not standard. Suck through the filter and light, but make sure everything is sealed on the light so it doesn't suck uncleaned air through and can only pull air from the filter.

Yeah these dimmable ballasts are great but they don't mention what it does to the bulb. If your lucky its mentioned in the small print in the manual. But many dont mention it at all. They also don't tell you that with super lumen option or boost option, as in running it at 660w it has to be started at 600w and manually turned up after the bulb has fired properly.
So yeah dim your bulb, it will still work, it can shorten the life span considerably but it is what it is. The ballast will be fine either way.

Good luck with the scrog, its a great way to maximise yield with low plant count. Ive done a few using 2" mesh, I found that slightly restricting and would go for something with 2.5-3 inch squares. Bigger than that (like a lot of nets on ebay) seems counter productive.

Best of luck getting everything dialled in dude.

coreywebster said:

The temp rise from ambient will depend on how much your AC can keep up with cooling the room when the lights are on and how much the air has to be exchanged to keep temps in range within the tent itself. Its something I don't have a formula for unfortunately. Except to say 1watt is 3.41 btu per hour.
You will have to set up and try it out.

If its an air cooled light then filter>light>fan>duct out of tent. That would probably be the only way to set it up given the dimensions of the tent. Unless its an inline filter and not standard. Suck through the filter and light, but make sure everything is sealed on the light so it doesn't suck uncleaned air through and can only pull air from the filter.

Yeah these dimmable ballasts are great but they don't mention what it does to the bulb. If your lucky its mentioned in the small print in the manual. But many dont mention it at all. They also don't tell you that with super lumen option or boost option, as in running it at 660w it has to be started at 600w and manually turned up after the bulb has fired properly.
So yeah dim your bulb, it will still work, it can shorten the life span considerably but it is what it is. The ballast will be fine either way.

Good luck with the scrog, its a great way to maximise yield with low plant count. Ive done a few using 2" mesh, I found that slightly restricting and would go for something with 2.5-3 inch squares. Bigger than that (like a lot of nets on ebay) seems counter productive.

Best of luck getting everything dialled in dude.

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Well I got my filter today, decided on going: out<-fan<-lights<-filter this will keep my lights off to the side a bit but gives me enough room to cram the filter and lights inside, I'm thinking the fan may have to go outside as the thing is almost 2 feet long.

And some bad news. Started hooking everything up in the tent and decided to do a dry run without the fan to see what I'll be up against and whether or not I should upgrade my AC. Well, went to go dim the ballast down to 250w and the damn button broke. It won't click anyone, so here's hoping vivosun can make it right. If they want me to send the unit back I'll probably end up just dropping the cash on a half decent one so I don't have any downtime as my seedlings are stretching on the windowsill at the moment.

On the bright side, the lights work, I just don't know how many watts I'm pumping out. I found if I throw the dial as far down as I can the lights are fairly dim so I'm probably on 250w and when put up all the way they're bright as hell so that's likely super lumen mode.

As for the dry run, with the flaps open and a 6" clip on desk fan inside and the top 8" sock open I'm at around 25% humidity and 30 degrees Celsius, which is a great sign because I've only got about 5 degrees to go and I'm sure the 6" fan will drop it that much and more.

At least things are coming together. Slowly but surely! This weekend will be most likely nothing more than trying to get the tent temperature consistent at around 25 degrees. Will post pics once the fan is here and put in place so I can get some better advice on my set up.

Thanks all and have a wonderful day!

Edit: Contacted Vivosun last night and they got back to me within hours. Should have a new ballast by next Friday now. Luckily the one I have will work in the mean time.

Really need to vent the outtake else where.its gonna get hot dude..I fitted mine to vent through the chimney.lol..I pull from the same room though..temps max out at 81°f at 22 to 24 inches away from canopy..I use a 1k hps 6 inch vent.i use pro mix bx..I've really enjoyed it so far..but I will be using coir my next run and a new line of nutes.

Squidkid said:

Really need to vent the outtake else where.its gonna get hot dude..I fitted mine to vent through the chimney.lol..I pull from the same room though..temps max out at 81°f at 22 to 24 inches away from canopy..I use a 1k hps 6 inch vent.i use pro mix bx..I've really enjoyed it so far..but I will be using coir my next run and a new line of nutes.

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I know it would be the proper and ideal way to go about things but unfortunately it's just not possible right now.

Now as far as set up goes I've got all my equipment. I'm just unsure of how to place the fan. I'm thinking of running the ducting from the light to the fan then the fan out the opening on the left side.

Does anyone have thoughts or recommendations on how to place things? With the current set up I may be able to get up to 2ft of growth before the canopy starts getting burnt.

Sorry about the mess of cords and such, I'm going to tidy it up and zip tie everything to the frame once I get the exhaust finished.

Hashishh said:

I know it would be the proper and ideal way to go about things but unfortunately it's just not possible right now.

Now as far as set up goes I've got all my equipment. I'm just unsure of how to place the fan. I'm thinking of running the ducting from the light to the fan then the fan out the opening on the left side.

Does anyone have thoughts or recommendations on how to place things? With the current set up I may be able to get up to 2ft of growth before the canopy starts getting burnt.

Sorry about the mess of cords and such, I'm going to tidy it up and zip tie everything to the frame once I get the exhaust finished.

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I've always blew the air over the light never pulled it..was how I was taught.your set up does not look bad at all.better than a lot that I've seen..you are on your way buddy..

Squidkid said:

I've always blew the air over the light never pulled it..was how I was taught.your set up does not look bad at all.better than a lot that I've seen..you are on your way buddy..

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I've been told by lots of people that these inline fans are actually more efficient when they pull instead of push. I figured I'd take their word for it and do it this way. If not, it can always be moved around.

I appreciate the kind words. I'm getting there, slowly but surely! Hoping I can have the seedlings in the tent for tomorrow.

this was a couple months back when I just finished setting it all up.not the prettiest thing but it does the job.lol