That's not dry enough. You have to gauge by picking up the pot and feeling its weight- usually if you feel a light pot that actually needs water, it will be dry nearly a full finger length. I'd drill 1/2" holes in the SIDES of those pots if you are having a difficult time getting them to use water fast enough in your conditions, since it's too late to add perlite. They are locked out and stunted because the roots are suffocating.