First time grow - I need help! Spotting and dying leaves - Pics

[Supersoap]

Okay, so this is my first grow. Been trying to look up as much as possible but so many things look similar to what's going on. Anyway, older growth is getting yellow spots and then dying essentially. Here's the info on the grow...

Strain: northern lights
Soil: ffof and happy frog mixed with light warrior
Lights: 400w mh 18/6
Time: 5 weeks into veg
Ph: between 6-6.5
Temps: 74-81

Been watering with distilled water. Fed half strength doses of big bloom once, two feedings of half strength big bloom/grow big twice. I'm thinking possibly the problem is with the distilled water?? I've grown plenty of vegetables using my tap well water with no issues...so thinking of switching to that instead of the distilled.

I can't see it being a N problem with all the N in the soil. Both plants are doing exact same thing. Any help is greatly appreciated.

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[Supersoap]

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[CO Finest]

You are guessing right. using distilled water you have took out things the cannabis needs.I would not use distilled water unless you're growing hydroponically where you're adding all needed nutrients for the roots, and there is no runoff.Distilled water is the softest(contains no minerals) water you'll find,excepting maybe pure rain. What happens is that any minerals in the growing medium are easily dissolved and/or attracted by the pure distilled H2O and if you're not careful with the runoff, a lot of your nutrients will get leached right out of the medium.
Distilled water is excellent when it comes time to flush the medium.

 

[Supersoap]

Thank you so much. I'm starting 12/12 later this week...should I just feed them the plain water next feeding or add nutes to it? I was going to feed them some tiger bloom as well. Hoping I didn't do too much damage to them.

 

[Richard Richardson]

Hi Supersoap, your plant looks great
Just give her plain water and tiger bloom now, before you switch to 12/12

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