1st indoor grow. Fair to say I have a few questions

  1. May have got too strong of a exhaust fan. 6" 390 cfm in a 4x4 (with a 1x4 separate room). Tried passive intake, but it wasn’t drawing enough air imo. I now have a small intake fan to assist with air circulation. The tent still has negative pressure, but that isn’t my concern (unless someone tells me that it should be). I can’t get my humidity up over 40% with temps around 25-29C. I’ve read about turning off the exhaust fan to raise humidity, but have also read that the air needs to be replaced every 5 minutes… I’d appreciate any thoughts on this.
    Oh, should intake fan be turned off if exhaust fan is turned off?

  2. i shared a few pics of my clones with some damage on the leaves. I believe it to be heat stress/burn, but not 100% sure. Was also thinking a nutrition issue, however, the damage is not on the edges and tips of the leaves.
    The newest leaves appear fine, so it’s possible that I have solved the problem by turning my lights down to 80%, but don’t really know. Any and all thoughts, comments, or tips are appreciated.

I dont know much yet myself but your exhaust fan is the right size. I wouldn’t go smaller. @Covertgrower may be of more help.


Suggestion here is to turn down the exhaust fan as low as it will go. There’s really no need for that much flow this early. This will help your humidity. You do have to have a fan in the tent circulating air around too. This still allows for negative pressure, which is only needed to keep the smell down. Air being replaced every 5 mins seems reasonable, in flower.

Why is the light even this high in veg? What soil is it? What are you feeding? Looks like phosphorus deficiency, with out knowing what you’re feeding. A lot of those deficiencies can be attributed to lighting.

I have a quite a bit of light in my set up, and I veg a 4x4 with just over 100w, to put it in perspective.
Welcome to the community @29sgordo29
Thanks for the tag kdawg.


I run a 6" exhaust and a 4" intake on both of my 4x4 grows. they are AC Infinity cloudline they both run of the same controler

1 Like

Piggybacking off @Covertgrower you can try to open up some of those bottom intakes to balance the negative pressure if you haven’t done so already. I did the same thing early on. Got overly ambitious with tryna prevent smell leaks. For my 3x2 rn I’m running 188cfm and it works like a top. My bigger fan is on standby till I get a bigger tent.


Excellent point. I did the same thing in my 4x4, mostly to keep the sides from sucking in so much.


Ok, so I’ve turned the light down significantly. It has an actual draw of 300w and i now have it set at about 40%.
I cut off the damaged leaves and haven’t seen any other signs of it.
As for what I’m feeding them, I’m a bit embarrassed to say…
I just have a pro mix garden fertilizer with 3-6-12. I used less than the bottle says, but possibly still too much?
I’m ordering a more suitable fertilizer today and would welcome your suggestions.

Also have some outdoor going into flower right now. One of them has a very dark colour to the new growth. Could it be the strain? Or a mold or rot?

Humidity remains low. Thinking humidifier might be needed.

@Covertgrower any suggestions on nutrients? I was looking at this hydroponics fert from indo. 3 stage pack with grow, bud, micro…
Also any comments on the above and the humidifier idea would be great.
I really appreciate you taking the time to read this and help.

1 Like

How low? You can hang a wet towel to increase humidity too. Other than that, I just work with whatever humidity there is. Dial back exhaust fans, and do what I can.

Nutrients, you asking about what kind to use? Or how much of what you have currently?

No trouble at all. I’m always willing to help with what I can. Sometimes I’m not clear, and just say hey I need clarification. Sometimes I’m posting on the go, and try and keep it short.

with fan running on low it gets down and stays at 30-32%.

I would use a wet towel for sure. I would just do the best you can. They’ll still grow in low humidity, just not as fast.

1 Like

I’m asking what kind of nutes. Been throwing this together on the fly and just used the pro mix until I find what I want.

I’ll try that. Just had fans off…up to 60% in 45mins. Going to monitor how long it takes to get back down when I turn the fans back on…maybe I can just cycle the fans

That’s an option if you’re not concerned about smells. Although they are pretty small and don’t smell much.

I use Jacks Nutrients. 321 recipe. It’s very easy. Part A and Part B. Plus epsom salt for magnesium. I had instant growth, after I switched from Canna. Most members are going to this. It’s really cheap too. So it’s definitely a win.

That works, but at what cost? Is there a schedule for the nutrients?
Liquid nutrients you’re paying for mostly water.

$50 for 3x1L Canadian $