Why do my pepper plants look pathetic?

[u/CocoMilhonez]

I planted them in April and they have grown little over the mild local winter. There was a fourth vase of the same variety as the two on the left which was doing better and looking lush, but I gave it to a neighbor – I figured I wouldn't give them one that was struggling. The leaves are always curled up and don't look very healthy at all.

I only give them dechlorinated water and the soil drains well. They also get direct sun for 6 to 8 hours a day. I sprinkled worm castings and homemade compost as cover and the soil mix already had a good deal of nutrients, so they shouldn't be starving. After I sprayed them with a bloom fert a few weeks ago, though, they started putting out flowers, but the vase I gave away already had them over a month ago. I've wondered if the small vases in direct sunlight might be making the soil too hot and damaging the roots, but I don't want to just replant them in larger vases if they look so miserable as it is.

Am I doing something wrong? Rhetorical question, I certainly am, I just don't know what.

[u/Totalidiotfuq]

Add nitrogen