First coco grow - help identifying issue with leaves?

Sick Plants & Problems
#1

Hello there OG

This is my first time growing in coco. I’ve always grown on soil and I decided to give coco a try. I’m using Biobizz Coco.

I’m hand watering daily. My water is 0.05 EC (25 PPM) and I use Grotek Cal-Max and Grotek Solotek Grow. I give 0.4 EC worth of Cal-Max (around 1 cc/lt) and the rest Solotek Grow up to 1.2 EC total feed strength.

My run off has steadily gone down from 1.8 to 1.4 each day. Although my pH comes out at 7.8, even though my watering always have a pH of 5.6 to 5.8

2 Days ago I noticed some rusted (or burnt) edges in some leaves. What do you think, calcium deficiency? salt built up? something else?

Currently I’m in week 4.

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Any ideas @TrevorLahey, @Mr.Sparkle ?

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#2

Sounds like to me that you have your answer

7.8 is about a bit higher than it should be with coco so you’re probably locking alot out …

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#3

I’d try a full shot of just solotek and skip the calmag for a few waterings. It’s a really good complete nute, I’ve used it before years ago. I find the need for extra calmag in coco is pretty exaggerated and standard nutes work just fine without.

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#4

Coco famously has a low initial pH. Keep the calmag. New coco will pull Ca ions from your solution. Check your runoff pH. I bet it’s way lower than 7.8.

Plant looks fine (wow so bushy), just a tad lime green from low pH.

Overly high pH results in dark green “crispy feeling” leaves with holes in them.

Keep doing what you’re doing. Only way to correct low pH is high pH inputs.

I use a 50/50 coco/perlite blend. Fixes the problems associated with pure coco.

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#5

Sounds like a pH/lockout issue to me.

What are you using to adjust pH? Some stuff is better than others and loses effectiveness very quickly. Might be worth it to mix up a batch of ph adjusted food and leave it sit overnight and see if the pH swing still happens.

Is the coco compressed brick (unwashed, unbuffered) or uncompressed pre washed stuff?

But I wouldn’t sweat it too much, that plant looks awesome and I dont really even see the rusting you’re talking about so it could just be growing pains. I’ve never grown a plant without a few rusty/spotted/yellow/necrotic leaves on it and I’d be super excited to have that plant in my grow right now!

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