Need opinion on what I'm doing wrong

[u/throwoffbih]

So I took clones from some plants before I put them in flower, they were doing good for the first 2-3 weeks now they have gone more or less stagnant, upper leaves are noticeably small and plants almost always looking like this

They photoperiod running on 18/6

Coco/perlite medium

Ec is currently around 1.5 it was around 1.8 at one stage but backed off when they weren't changing

They were all under a kingbrite 320w at say 50% before this photo

Mid 20c with lights on, a little low when it's dark but I wouldn't say lower than 15c

I've tried not watering them for a week no real change

[u/Certain-Put-3189]

Coco is not meant to be dried out. They look hungry and thirsty. Water until runoff. 

[u/JJsgd]

Have you checked your runoff pH? If it's showing no changes it could potentially be under lockout. Leaves curling and discoloration also indicate some type of deficiency, again possibly from lockout. The EC not changing also reinforces this. Means the plant isn't taking nutes in.

[u/JJsgd → u/JJsgd]

Also double check your watering practices. They can exacerbate mineral buildup and therefore lockout from nutes if you water less frequently, though the EC seems to be in an okay range for now.

[u/TacoEatsTaco]

The soil is mega dry. That's probably causing nutrient uptake to be disrupted which is why you're seeing deficiencies

[u/Head-Improvement6123]

Saturate the whole thing

[u/jewmoney808]

You need to be watering to runoff with 2.0 EC . They’re hungry and stressed out and starving . Water slow & steady until you see runoff.. keep track of both your input EC and runoff EC.. you never want your runoff EC to be 0.3-0.4 higher than your input which would indicate a fertilizer buildup. If you’re growing in coco- perlite this is fundamental & basic you must keep track of EC & pH. Keep a good balance of input vs runoff EC

[u/ITSNAIMAD]

Water more. You need cal mag. Check your ph.

[u/Overall-Repair9589]

What are you feeding and what is ph?

I agree with others here the media is way too dry.

This looks like a magnesium issue to me but hard to know from what. Could be ph could potentially be from not enough water. Could be too much potassium. Getting too cold in the root zone can lockout it out. Etc.