Stunted growth leaf issue

Does anyone know what this could possibly be ? I keep discovering numerous possibilities and end up confused to what I should narrow it down to!
Veg week 3
3 strains
Grown in coco 600w led that is dimmed down to 30% at a height of 600mm
Sealed room with co2 at 800ppm
Room temp is around 24C and 60% humidity
I think the vpd is in an acceptable range
Water just a single part grow nutrient EC 1.4 don’t usually water till runoff but never really had a problem doing it that way either, PH is around the 6 mark. Plants were good when first taking off as clones , unfortunately some of the clones I received from a friend were in soil so when transplanted I shook all the soil off the roots which I understand would of shocked them abit, but not for weeks after, and they were starting to grow after transplant anyway so didn’t think that was causing my issue.

Stems are reddish/purple slow stunted grow, light green leaf coverage and bottom leaves getting light between veins and then slowly brown/rusty edges and spots


Welcome to the forum.

A few random comments and suggestions:

Node spacing shows that the plant could use more light. It’s possible that your light isn’t actually 600 watts. What make/model of light are you running?

A good rule of thumb for adequate lighting is ~200 watts per plant of quality lighting (LEDs built with Samsung LM301 series diodes.)

Temp and RH are good. I wouldn’t worry about spending much time chasing VPD. Many growers just focus on >50% RH in veg and <50% in flower.

I would shoot for 2.0.

5.8 is the sweet spot for coco.

Is normal.

It’s normal for a plant to shed its lower leaves as the plant matures.

I would spend time and money on something else. Cannabis needs 1,300+ PPFD before the plant will even start to use excess CO2. You can’t get there with your light. Additionally, CO2 requires elaborate environmental controls (a closed loop system, high lighting, high nute levels, higher temps, oxygen to the roots,…) that hobby growers don’t have the budget or experience to replicate. Very few experienced growers supplement CO2. Those who do have implemented elaborate environmental controls.

Which nutrient product are you using?

Looking pretty good with those plants. Make a few tweaks and you’ll have a lush, impressive garden.

Happy growing!


Thanks for your response mate !

The light is 600w just turned it from the 400w setting to 250w yesterday because I wasn’t sure if it was to much for then as this is first run with the LED, had it at about 500mm from canopy but raised to about 700mm also to eliminate the possibility for excessive light

The one part nutrient is just a local brand but usually use growth technology

Yeah the CO2 I wasn’t sure on if it would be beneficial atm or not but thought I’ll chuck it in anyway, plan was to veg under the 600 led and then flower them under 2x600 and then that’s when I would like to implement the Co2

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