How much is too much air?

Ok, so I have some Big buddha cheese flowering, just finishing week 6. Iv got a lot of oscillations fans in the room. I had mold on my last grow so I think I was a bit over kill this time. There’s one 16inch covering the the room itself then I have small oscillating ones over each canopy and one below each canopy. So 7 fans total. The plants can be seen moving with the air circulation but not aggressive or anything.

In week 4 or 5 I was feeling some of the leafs, they were coated in resin, really really sticky stuff. But over the last few days maybe a week, iv noticed those same leads aren’t so sticky anymore. They feel dry to touch, almost like the thc has dried up on the leafs.

Is this possible? Have I got too much air moving?

yes it's possible, and you probably do. get a small dehui, and turn at least half of those fans off.
the reason your leaves feel dried out is they are dried out. plants need to transpire, both to cool themselves, and the osmotic action helps pull nutrients up from the roots into the rest of the plant. but transpiration takes effort, if your plants are working overtime transpiring, they can't put a lot of attention into growth, and it also makes it easier to overfeed, the increased transpiration causes increased osmotic action, so the plant is drawing up more water, which contains nutrients.....

Roger A. Shrubber said:

yes it's possible, and you probably do. get a small dehui, and turn at least half of those fans off.
the reason your leaves feel dried out is they are dried out. plants need to transpire, both to cool themselves, and the osmotic action helps pull nutrients up from the roots into the rest of the plant. but transpiration takes effort, if your plants are working overtime transpiring, they can't put a lot of attention into growth, and it also makes it easier to overfeed, the increased transpiration causes increased osmotic action, so the plant is drawing up more water, which contains nutrients.....

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Thanks man, you explained it very well. I will turn off some of these fans so.

When I only had the 16inch oscillating I was worried about some of the buds at the back of the canopy not getting air through. But after thinking about it, it was around the time i added the extra fans that I noticed the dry leafs.

i just have two fans in veg area and my flower room, and they're both set up the same way, one low, blowing pretty much across the tops of the pots, and one higher, blowing between the tops of the plants and the light. the bottom one sets on the left and blows to the right, and the top one sets on the right and blows to the left, so it sets up a slow cyclonic action

The trick is to use no more wind than necessary.
You just don't want any microspots with high humidity, like two leaves sweating on each other.
But, you also want to constantly stir away old air from the plant.

The goal is to have the same humidity everywhere, no more. The actual humidity should be controlled by the rest of your equipment.

Roger A. Shrubber said:

i just have two fans in veg area and my flower room, and they're both set up the same way, one low, blowing pretty much across the tops of the pots, and one higher, blowing between the tops of the plants and the light. the bottom one sets on the left and blows to the right, and the top one sets on the right and blows to the left, so it sets up a slow cyclonic action

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I like the sound of your setup. I have a feckin tornado in my room so lol

I have a 2.4m2 tent. On my last grow I only used the big 16inch on oscillate but obviously it wasn’t circulating the air around the canopy just blowing at it. Then I thought, more fans!! But I still don’t have the air circulating it’s just a windy mess. I will have to remove some fans and reposition the rest so it creates an even breeze. I still have maybe 3 weeks left to harvest so hopefully I haven’t caused to much damage.

You need 10-15 ach (air changer per hour) to grow cannabis and not have mold or mildew issues. A good dehumidifier too if moving the air isn't bringing down RH enough.

To do this you multiply your exhaust fan cfm x 60 and divide it by the volume of the room. For example...lets say you have a 8'x 8' x 8' space and you have a 4" centrifugal fan rated for 180 cfm. 180 x 60 = 10,800 -the volume of the space is 512 cu ft - so a 180 cfm fan on full will give roughly 20 ach - in this situation I would dial back the fan controller and run the 2 oscilating fans on low setting.

you ought to be fine, any damage should be minor

McStrats said:

You need 10-15 ach (air changer per hour) to grow cannabis and not have mold or mildew issues. A good dehumidifier too if moving the air isn't bringing down RH enough.

To do this you multiply your exhaust fan cfm x 60 and divide it by the volume of the room. For example...lets say you have a 8'x 8' x 8' space and you have a 4" centrifugal fan rated for 180 cfm. 180 x 60 = 10,800 -the volume of the space is 512 cu ft - so a 180 cfm fan on full will give roughly 20 ach - in this situation I would dial back the fan controller and run the 2 oscilating fans on low setting.

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Nice!! So how should I work it out if I’m running the extraction through 3 air cooled hoods and a filter?

I have an 8inch Gekko 1500m3 / 882cfm. The room is 11.52m3 / 512c/ft. The fan is inside the room, 8inch filter is connected directly to the fan and the air is pushing through 3x 6inch air cooled hoods. I’m assuming this would add more drag. Maths was never my strong point and the calculator can only do so much

Here’s how it’s setup. Best I can do on the phone lol
_____________
| |
Light Light
| |
| Light
Fan - Filter |
Outside tent


**edit**

Well that diagram failed miserably haha

that looks right, if "outside tent" is your exhaust

I think a 882 cfm 8" fan is too big for that space. You do have some static losses (resistance) due to the air cooled hoods andfiltration, but not that a big amount really so a 4" with a fan controller is about right. I'm a novice grower to tell you he truth but I do industrial ventilation for a living so I'm not sure what effect (if any) too much airflow would have on a growing plant.

Roger A. Shrubber said:

that looks right, if "outside tent" is your exhaust

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Yep, outside the tent goes out through the fireplace. Before, I had it ran into my house but the temps were hitting 32C

McStrats said:

I think a 882 cfm 8" fan is too big for that space. You do have some static losses (resistance) due to the air cooled hoods andfiltration, but not that a big amount really so a 4" with a fan controller is about right. I'm a novice grower to tell you he truth but I do industrial ventilation for a living so I'm not sure what effect (if any) too much airflow would have on a growing plant.

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Ok, thanks for that info man. I won’t be able to do much at the minute but I will start making some changes for my next run. I will use a separate fan for the lights and filter to save some hassle

Fans have been repositioned and turned down to the lowest setting. Each fans facing the opposite corner of the tent so not directly on the plants. There is now a “gental” breeze

Thanks for all the help guys, hopefully they will start to pack on some more frost before harvest time