That looks like a very coarse starting mix, Ashley.

Many gardeners recommend soil-less, sterile, finely-screened medium for starting seeds. It should both hold moisture and drain well. All that is probably safest. I also like to have the containers quite full and think that this exposure of the surface of the mix helps with ventilation and reduces risk of fungal diseases.

Bok Choy is a cool weather vegetable but extremes in temperature stresses plants. Seedlings are tender. They need light for photosynthesis and growth because only so much can be expected from seed leaves and the initial roots.

Steve