whats this color on my plant leaf

could you tell me whats this color on my plant what kind of deficiency is it?

Looks like early mag def I could be wrong

You're overwatering your plants. I see algae on the perlite. Overwatering can cause the soil to go anaerobic starving the plant of oxygen and preventing the plant from taking up nutrients. How come you left so much room in those pots? They're small containers. You want to fill them up as much as possible.

more perlite will assist drainage

next time you water

lift pot THINK first to water or not

good luck