A plant that size should be started in a small 3" seedling pot with a "seed" potting compost or proprietary soil less compost.Plants do best when they form a tight root ball, when it reaches 4" to 6" repot in the final grow pot with a 50 50 blend potting mix and perlite. It looks like a rediculous amount of perlite to use but mary likes sandy well draining soils.
Get rid of the foil, you are better off with white plastic trash bags (they also suck)...mylar is the best. Foil creates hot spots. You shouldn't need anything with bulbs as close as they should be right now.
Flourescent bulbs 2 inches away until you repot, then treat as a young plant.
Also watering is a factor, wait until the "soil" is dry to the touch at the surface and begins to pull away from the sides before watering. Your plant might be beginning "damping off" basically rotting of the roots from to much water.