Have you watched Craig's videos?. He starts a dense planting indoors, very few trays
and take up no room at all. Sprouting in a warm office window on a table.
Steril mix will have no gnats. Coir or flourDry for seed starting.
He then pots up in the garage keeping all mess and massive quantity out of the house.
Weather is warmer so the garage may be fine. A table and a shelf unit is probably all
you need. The shelves w/ light set-up could be covered for warmth.
Do you have any houseplants? That could be the incubator of gnats.
Maybe its her fault...