Don't be afraid of worm castings they are truly mother nature's gift, at your plants age
and the soil mix you have you might need to use a mild fertilizer, I like Gen. Hydro.
Flora Nova they are simple 1 part nutes good for starters, or Fox Farm Go Box is very
good to. Start any fertilizers at quarter strength.
Aerate the soil and water a little more than we see in the pics. the soil looks quite dry.
You can also get a Mycorrhizae culture to add to your soil these are the microbes that
break down the nutes so the plants can uptake their food.
Keep us posted on your progress.
Keep it green and growing.