Proper clip-on-fan placement?

I only have one plant left right now in a 4x4.
I have a single 6" hurricane clip-on fan clipped to a t-bar on the ceiling, way up above my light. It's set on 1 (out of 2) & pointed downward at the plant... creating a constant gentle breeze on plant.

What is your preferred placement area & do you have your fans blowing directly onto plants?



With passive intake bringing in air from all sides at bottom, do I even need a fan on the floor?

I have a 6" fan above my light and then a little 4" fan near the intake in my photo tent. In my auto tent I have two 6" fans set up the same way. Both tents are 32x32x63 and my first grow so I'll see which I like best and tweak as I go. So far, I like two fans in addition to the exhuast. Your plant already looks great. IMO an added fan wouldn't hurt anything.

I use a 40" X 40" tent and I use 2 small Sun Leaves (brand) clip on fans. I place one pointed downward and the other directed just above the canopy and run them constantly. I also run a charcoal filter and 4" extraction fan that draws air in at the lower end of the tent and exhausts it out the top of the opposite side that creates a constant air exchange. I look for some of the leaves to move in the breeze but never a constant flow directly at any one area....kinda just each fan helping the other to "stir" the air in no particular way.

Ok I now have one (on roof) pointed toward the LED driver & one on the right side, installed at light level... above canopy...blowing across. Thoughts?

That plant is going to stretch nicely over the next two or three weeks. As the canopy becomes denser, don't be afraid to experiment with putting the little fan lower near the intake to blow fresh air up through the canopy. I can't wait to see it in a couple of weeks. Reminds me of what my current grow looked like at the start of flower.

odessa said:

That plant is going to stretch nicely over the next two or three weeks. As the canopy becomes denser, don't be afraid to experiment with putting the little fan lower near the intake to blow fresh air up through the canopy. I can't wait to see it in a couple of weeks. Reminds me of what my current grow looked like at the start of flower.

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Any suggestions as far as Trellis/support etc, or would i be fine just leaving it as is? All I've done so far is top it.

DrDukePHD said:

Any suggestions as far as Trellis/support etc, or would i be fine just leaving it as is? All I've done so far is top it.

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This run I grew bag seed and didn't know what the sex would be so I topped twice in veg instead of using the net. My next run I'm doing feminized seeds and it will be my first experience with the net. If they are anything like mine were topping should be enough.
That's how much stretch I got.

Blowing down on a light will push the hot air at the plants... I have two hung 6" fans at each end of my tent they're about 4" above canopy and angled slightly down across the plants. If I run a fan on my light It's across or slightly up to push the hot air towards the exhaust vent.

LeastExpectedGrower said:

Blowing down on a light will push the hot air at the plants... I have two hung 6" fans at each end of my tent they're about 4" above canopy and angled slightly down across the plants. If I run a fan on my light It's across or slightly up to push the hot air towards the exhaust vent.

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Makes sense and I just adjusted my fans accordingly. I was pointing the fans to the light to help cool the light, but I suppose it can just as easily blow the air away from the light without pushing the hot air into the canopy. Thanks!

odessa said:

Makes sense and I just adjusted my fans accordingly. I was pointing the fans to the light to help cool the light, but I suppose it can just as easily blow the air away from the light without pushing the hot air into the canopy. Thanks!

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I spent a few days playing with this...I generally haven't had additional cooling up top beyond the pin-head heat sinks on my HLG's so I put a 6" fan up there, really just blowing at a slight angle down and across the sinks (there are 3 sinks)...and I noticed that my temp readings at plant level raised from ~82f up into the low 90's, so that was a no-go for me.

LeastExpectedGrower said:

I spent a few days playing with this...I generally haven't had additional cooling up top beyond the pin-head heat sinks on my HLG's so I put a 6" fan up there, really just blowing at a slight angle down and across the sinks (there are 3 sinks)...and I noticed that my temp readings at plant level raised from ~82f up into the low 90's, so that was a no-go for me.

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My temps stay in the high 70's but I wasn't even thinking that I was trapping that dank air in the canopy.

LeastExpectedGrower said:

I spent a few days playing with this...I generally haven't had additional cooling up top beyond the pin-head heat sinks on my HLG's so I put a 6" fan up there, really just blowing at a slight angle down and across the sinks (there are 3 sinks)...and I noticed that my temp readings at plant level raised from ~82f up into the low 90's, so that was a no-go for me.

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Could definitely be helpful in the winter months for some grows who struggle with low temps

Add a trellis, I waited too long and now I have multiple locations that are different heights or blocking another node. I have a 4x8, with one fan at the bottom oscillating and 3 6in at canopy level just moving air around. then my exhaust is directly above my led's

EvilJ said:

Could definitely be helpful in the winter months for some grows who struggle with low temps

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I'm in a place that has cold winters, and the bigger problem for me is the lights-out period...even with winter temps outside, I'm still in the upper 70s and low 80's with lights on. Of course that depends on how much wattage & the size of your tent, but my tent is roughly a 4x4 in cubic footage and I'm running 675w.

RIS said:

Add a trellis, I waited too long and now I have multiple locations that are different heights or blocking another node. I have a 4x8, with one fan at the bottom oscillating and 3 6in at canopy level just moving air around. then my exhaust is directly above my led's

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I should install a trellis for this shorty?

DrDukePHD said:

I should install a trellis for this shorty?

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It definitely would help use the stretch to your advantage by opening as many bud sites to light as possible. The only reason I didn't use a trellis on my current grow is that I didn't know what the sex of my bag seeds would be. SOo I topped twice and used LST and lollipopping. I was able to get a decent canopy. On my next run with feminized seeds, I'll be using trellis nets extensively.

I had a whole thing written out but here is what im going with...

Yes

odessa said:

Makes sense and I just adjusted my fans accordingly. I was pointing the fans to the light to help cool the light, but I suppose it can just as easily blow the air away from the light without pushing the hot air into the canopy. Thanks!

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My carbon filter is now working even with the tent door open. You helped out so much today! Thank you @LeastExpectedGrower

odessa said:

My carbon filter is now working even with the tent door open. You helped out so much today! Thank you @LeastExpectedGrower

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Glad it works for you.

Also, I find that if things are really stinky with the door open, once I'm done in the tent, I crank the fan up to peak for about an hour and it pulls not only the air from the tent out through the filter but the intake also sucks the stink out of the 'lung room' and the whole floor that has my tent on it... which can be a handy tactic if you've got people who might visit later but you need to get in your tent and do a few things.

You want to have passive airflow where the fans aren't directly blasting the plants, so aim it where it will naturally just move air in the tent without directly blasting plants. With that small of a fan and with how far it is it probably wouldn't hurt to aim it straight at the plants honestly.. Too much airflow you'll notice your plants whipping around quite a bit or not bouncing back to where they naturally rest without wind.