middle leaves curling up and yellowing

I have 4 plants outside in a greenhouse. 2 are doing AWESOME (northern wreck and harlequin) and 2 that have problems. They've all been treated exactly the same as far as water and nutrients.

the 2 with issues have leaves curling up and yellowing in the middle of the plant. could over watering have done this? I mixed in worm castings when I up-potted them. Maybe those two strains are getting nutrient toxicity from this? Please help. Pictures below.

I don't think it is over watering. Zinc deficiencies will display on middle leaves but I don't know what a zinc deficiency even looks like, I don't think it is common in soil grows. A boring insect could cause localized damage like that as well. More info on your feed rates and products might help. Doesn't look like over feeding issue so maybe under feeding? More details please.

I haven't given them any nutrients yet. Just high quality soil and worm castings. They're about 5-6 weeks old. I mixed in the worm poo about two weeks ago and then this. Mixed it 50/50 with the top soil I added when I put in larger smart pots. Like I said though, the other two plants look perfect.

Probably time to feed them then.

Ok thanks. makes sense. Anyone else agree or disagree?

Time for feeding....