Leaves going yellow

Hi

A lot of yellow is now appearing this can't be nute burn as my EC is very low, What else could cause this?

These are about 3 weeks old on 18 hours light an Canna Nutes EC is 0.5

Not all the plants have done this only some.

Are they all the same strain? It looks like the new growth is leeching N from the larger, older leaves.

edit:
how long since planted? How established are the roots?

There is a period of deficiency with larger clones as the roots establish themselves... a period of not enough roots to feed the existing plant matter. I saw it in my last grow where I started with large clones. Once the roots get going, though, my plants just brush off any prior minor deficiency, go deep green and explode.

edit 2:

Wondering why your grow area looks all wet. Are you foliar spraying? If so, mist lightly with a fine atomizer without drenching your grow area. You're inviting mold or algae if you keep your grow area drenched like that.

yes all the same strain, What does N mean an how can i fix it?

Cheers

Oh, planted three weeks ago. Sorry. How developed are the roots? I would imagine they're pretty well established after three weeks.

N = Nitrogen. What are the NPK numbers on the base nutrient you're using?

0.5 EC is like 350ppm? Try increasing your concentration gradually.

Edit:

What you're seeing isn't a critical disorder. You'll be fine.

those are lovely clones btw, they'll shake it off. I think they're just a bit underfed.

plants are hungry feed more strength and add 1/4 teaspoon of epsom salt

DrFever said:

plants are hungry feed more strength and add 1/4 teaspoon of epsom salt

Click to expand...

Or calmag.

i conur with adding cal/mag and N. and incresing your EC/PPM. also keep a eye on your P.H

stop the foliar feed with the lights on, the droplets will act like a magnifying glass and burn your leaves. Those plants look like clones left in the cloner to long without adding nutes. Just add or foliar feed some time of N dominant nute formula, it should be labled "Grow" I feed low ec too, about .8 to 1.2 max but all plants are different. I wouldn't go over 1.2 EC until you are confident. If you've got the nutes correct, the new growth will be nice and green.

they look hungry, feed them more. also a highly overlooked deficiency is iron (Fe) because it appears allot like nitrogen (N) and can actually cause a (N) def because it aids in assimilating and reducing nitrates properly (this is where calmag comes in handy) use it always and use allot of it. your leaves appear to have chlorosis (intense yellowing of the leaves) prably caused by low iron, get you some calmag! i was told by a old school grower that he swears running allot of calmag could allow him to run a much higher feeding schedule, i thought "bullshit" so i looked into it and sure enough calmag usually has iron in it so now when i add calmag to my res i double the dose and my plants look great. when plants are actually in a bad way adding high doses of calmag pulls them out of it quickly.