Humidity is out of control

[Doc420grow]

Hi guys, new here to the thread...just wanted to get some insight on what i can do here to help my northernlight auto. This is only my second grow and I didnt have many issues the first time around luckily, but its alot hotter this time of year and my humidity Is going ballistic.....here's my set up

Tent - Topolite 3x3x5
Exaust Fan - Hydrocrunch 6 inch 410cfm with carbon filter
Intake Fan - Ipower 6 inch 200cfm

Light - Hydroplanet 2x8 T5 Setup (8 bulbs)
(6500k and 2700k)
Humidifier
Dehumidifier
2 clip on fans
1 tower fan
IHC-200 humidity controller

Medium - Coco coir with perlite mix
Nutrients - Fox farm trio and Calmag

So basically, I feel as if I'm getting plenty of airflow and circulation in my tent which should mean low humidity, right?...I have good negative pressure and the plant looked awesome until just recently, I fed her which i know can spike the levels but it hasn't stopped. I'm at day 31 almost into flower from what I can tell and I'm trying to keep my level down to 55% I got it to stick at 61.4% until this morning....its at 73.2% and nothing I change gets it consistantly even under 70. My room temp with ac right now is 71 with inside the tent at 77 as well as circulating fans through out my room.

Also I have noticed the tips of the leaves curling up and possible nute burn? Even though I feel like I'm not using enough. Lower leaves are obvious, had some ph issues.

Am I just being hard headed and not seeing something so simple?? Please and thank you to anyone with some insight.

 

[Weaselcracker]

That humidity won’t harm the plants in my experience. It can become an issue with mould in late flowering, but even then 60-70 should be ok for most strains except the most mould prone ones. I have been at that RH level or higher for years.
A little bigger dehumidifier will help- even if it’s your intake air that is a moisture source.
As for your yellowing issues I see Mr Krip around so I’ll let him speak to that- but what’s your PH, and feeding levels?

 

[Doc420grow]

That humidity won’t harm the plants in my experience. It can become an issue with mould in late flowering, but even then 60-70 should be ok for most strains except the most mould prone ones. I have been at that RH level or higher for years.
A little bigger dehumidifier will help- even if it’s your intake air that is a moisture source.
As for your yellowing issues I see Mr Krip around so I’ll let him speak to that- but what’s your PH, and feeding levels?

I've been keeping my PH st 5.5-5.8 recently, and I feed every other 2-3 days depending on what the plant is looking like, also rotating using PH'd water with cal mag. As for the fox farm trio I am only using 10ml of big bloom and 5ml of grow big at the moment per gallon, as well as 5ml of calmag

 

[HayStack]

I'm not sure where you live or what the humidity outside the tent is. But I live in the SF Bay and it can get pretty humid around here. I have a single Probreeze dehumidifier in my tent and the humidity doesn't get higher than the low 50's. If you are in a high humidity area, maybe you need two.

 

[Mr. Krip]

Looks like magnesium deficiency. I'd check PH, if high, flush & adjust if needed. Also, if you're using RO water, make sure you add Cal-Mag. Even with proper PH, you may need to add Magnesium if using RO (and, it's usually a good practice!).

 

[Weaselcracker]

Coco isn’t my usual grow medium but when I’ve used it I fed every time- never gave them plain water or just calmag and water as you’re describing.

 

[Doc420grow]

I'm not sure where you live or what the humidity outside the tent is. But I live in the SF Bay and it can get pretty humid around here. I have a single Probreeze dehumidifier in my tent and the humidity doesn't get higher than the low 50's. If you are in a high humidity area, maybe you need two.

Very possible brother thank you, I'll have to check these out. Worst part about it is I'm going out of town for 4 days so I need it under control before I go .

 

[Mr. Krip]

I've been keeping my PH st 5.5-5.8 recently, and I feed every other 2-3 days depending on what the plant is looking like, also rotating using PH'd water with cal mag. As for the fox farm trio I am only using 10ml of big bloom and 5ml of grow big at the moment per gallon, as well as 5ml of calmag

Hmmmm.....

What's your run-off PH?

 

[Doc420grow]

Looks like magnesium deficiency. I'd check PH, if high, flush & adjust if needed. Also, if you're using RO water, make sure you add Cal-Mag. Even with proper PH, you may need to add Magnesium if using RO (and, it's usually a good practice!).

Definitely will be checking today, last time I tested runoff it was 6.4 so it was higher which worried me

 

[Doc420grow]

Coco isn’t my usual grow medium but when I’ve used it I fed every time- never gave them plain water or just calmag and water as you’re describing.

I have seen this more than once and I will most likely lean more towards your advice.

 

[Doc420grow]

Hmmmm.....

What's your run-off PH?

6.4 last time I checked, I have a feeling it must be higher now....I watered with calmag 2 days ago and forgot to check but it's still a bit damp...do you suggest I just flush it out today or wait till its dry?

 

[Mr. Krip]

Definitely will be checking today, last time I tested runoff it was 6.4 so it was higher which worried me

Sounds like you may need to flush the medium. Whatever PH your medium is at, it's raising the PH of your 5.5-5.8 nutes to 6.4, so it's got to be high.

 

[Weaselcracker]

To me a runoff ph of 6.4 would seem normal. What comes out is always higher than what goes in, at least in my grow .

 

[Doc420grow]

I will buy better dehumidifiers and test my run off as you all have said and see where it gets me. Appreciate the fast responses and I'll keep everyone up to date. Always taking criticism if you have any as well. Thanks again.

 

[Weaselcracker]

If nothing else I’m sure the problem isn’t your humidity. It wouldn’t cause this.

 

[Blew Hiller]

If your fan is directly blowing onto your leaves that can cause wind burn (curled leaf tips)....if it can oscillate, do so.

 

[Doc420grow]

If your fan is directly blowing onto your leaves that can cause wind burn (curled leaf tips)....if it can oscillate, do so.

Funny you say that I literally just double checked that as well...good catch

 

[Doc420grow]

Ok, so update....I tested my runoff...........8.64......any insight? Wtf lol how do you go about flushing an autoflower?

 

[Weaselcracker]

There’s a good coco grower named @Cultivator who could help you better than me since coco isn’t really my thing. Not sure why such a high ph. I would suggest feeding it more consistently though, and probably more often. Getting good runoff when feeding helps, especially if your nutrient mix isn’t always perfect.

 

[Mr. Krip]

Ok, so update....I tested my runoff...........8.64......any insight? Wtf lol how do you go about flushing an autoflower?

How to lower the pH of coco coir

If your runoff pH is too high or too low, you can fix pH issues easily by flushing the coco coir with properly pH’d water.

For example. if your runoff shows a high pH of over 6.2, try running the next few waterings around 5.6 to 5.7 with about 25-30% runoff and you can bring this down easily. For a pH over 6.5, you’re entering the danger zone and you should flush several gallons per pot plant at 5.6 to make sure to correct the issue more quickly.