HELP! Yellow Leaves with Dark Spots

[realmofgeorge]

Hey there guys, on my first grow and I'm having some problems with my plants. On all my plants they are a yellowed and some are experiencing dark spots (different plants have different kinds of dark spots). It's been a problem for a little while now but I've had trouble diagnosing it. Each plant is in a 5 gallon pot with purely coco coir, I feed twice daily 1.5 litres of water to each plant (one with nutes, other with just ph balanced water always between 5.5-6.2), I use canna a + b at a ratio of 2.5 mls per litre with 2.5mls per litre of cal mag too. I have two tents, each with a 600w HPS lamp with the temps ranging between low 20s Celcius to just above 30 Celsius on hot days. I apologise for the photos being so yellow due to the bulbs, wish I could take a good video but the flicker is too much to really see whats going on. Any help would be appreciated and if anyone feels like baby sitting me through the rest of my grow that would be a god send. Thank you

Imgur: The magic of the Internet

[YYCannabis]

Hey, George. Welcome to GWE.
I grow in hydro, but not coco. I might be a bit off with this, but why do you feed twice a day? I’m wondering if your second feed is washing away the nutrients from the first feed.

Some more details would be helpful to us. Temp/humidity/strain etc

[realmofgeorge]

Hey, George. Welcome to GWE.
I grow in hydro, but not coco. I might be a bit off with this, but why do you feed twice a day? I’m wondering if your second feed is washing away the nutrients from the first feed.

Some more details would be helpful to us. Temp/humidity/strain etc

https://www.cocoforcannabis.com/watering_coco/ from what I gather from this website in coco I should be watering up to 5 times a day, I alternate between nutes and non-nutes to eliminate salt build up (suggested to me by a video, might not be correct information).
Temp: 20c during the day, 29-32c at night
Humidity: 60ish%
Strain: Critical Orange Punch by Dutch Passion
I haven't really been measuring run off although I understand it's important, should I be having more of a focus on this aspect of growing?

[dilvish]

by the looks of those pictures I'd say overwatering, too high temps and likely humidity and light burn. They could also be rootbound if the roots are already growing far outside the pot.

First and foremost you need to regulate the temp and humidity better.

Second you don't just water as many times as someone says. Check the pots. if you can push your finger into the coir up to 2 inches and still feel moisture, wait another day.

Third watering first with nutes then just plain water is either washing away all the nutes or diluting them to the point where the plant isn't getting enough. In coir you should simply flush the pot thoroughly with properly PH'd water every second or third watering. Watering should be roughly every 2-3 days under ideal temps.

[TOKABIGONE]

Also you need some kind of riser between the pot bottom and the saucer, even a small amount of gravel so you are not sitting in water and drawing it back up. My guess is most of your problem in being way, way to wet. They're drowning!

[JeffInCanada]

Hi realmofgeorge
Here is a link all about coco: https://www.growweedeasy.com/coco-coir
Below is a link all about watering. Hope this helps.