What is going wrong with my plants?

[BukBudz]

Hi guys,

What's going wrong with my seedlings? 21 days since germination.

It's been incredibly hot and dry where I live - they spend more time indoors than other plants I've grown before simply because they'd cook outside.
I went away last week and they got a little too much water from my brother, rescued them by transplanting them into new soil/pots and they bounced back. Now they're struggling again and I'm stumped.

Any ideas?

 

[Squatch61]

The first photo looks like some light burn leaves are curling up and they look under watered. I just went through this I use five gallon smart pots and was using a drip system. The drip system only watered the top 1/4 of the soil leaving the rest bone dry. Pick up the pots if they feel light completely soak the soil wait seven days and repeat you need to deluge them and then allow them to dry out. Get in the habit of picking up the pots to determine when they need to be watered. Also what is your water and soil PH improper PH will cause nutrient lockout.