im fairly new to all this as well, but i've had 3 successful grows

i would say it's probably your waters ph

also i never heard of adding epsom salts to the soil?

normally epsom is for foliar feeding

i also heard that it's difficult to grow in the attic due to the constant changes in temperatures

i'd also like to mention that you may need a more powerful light source

see what the other more experienced growers think

i would flush em with ph'd water myself

oh and reduce the watering, only water when the pots feel light and the soil feels dry(stick finger in)