They're about 2 inch tall

They'll also grow much better if you separate them so they each have their own pot.

Are they indoors or outdoors?

They're indoors under LED lights but inside a covered latch box at night to prevent gnats from getting in the house. I only bring them outside at day, for about 4 or 5 days. The temperature outside is now 50-58 during daytime. I fed them MG 24-8-16 last week. Sometimes I think the sealed latch box retained too much humidity during a month of growing

I used to grow sauce tomatoes. Tomatoes do not grow when the temperature is 50 degrees.

Does the sealed latch box have ventilation?

I used to start plants in plastic boxes sold for clothes storage. I would drill vents, place in the sun, with a thermometer, move and adjust the ventilation.

Where are you, how old are you?

The plastic box does not have ventilation which could be the problem. I open the lid at daytime 10am-4pm for the vapor to escape then close the lid at night. I live in Ontario, Canada. I'm at my 30s (not sure how my age is relevant)

It's the low temperature that is causing the slow growth, but that is a good thing because you want them to be stout and sturdy, rather than tall and skinny. I wouldn't even pot them up for a while as they don't look too big for their pots. I think that the LED light could be burning the leaves as I have had the same thing with my new LED light. I found that 2" is too close for LED lights and 8" is better.

Linda

Thanks everyone!

Canada is cold, your age because you have no experience and I would address a child differently than an adult.

What are the temperatures in the box.