If you have a fabric pot bigger then 10 gallons it is easy to start a pot indoors. You can use composted manure or leaf mold with some amendments (kelp meal, gypsum, neem, or whatever I have.) Also you can just add an organic fertilizer mix like Espoma Tomato Tone, which carries a variety of things. You will also need something to keep the whole thing from compacting, I use rice hulls because they break down and are full of silica. You can use perlite, pumice or something else. Don't worry about the bugs you bring in. The creepy crawlers in soil typically are in the soil for a reason and don't want to leave said soil. I have a worm bin in my mancave in my house. My buddies are always like, "dude your going to have bugs in your house from that worm bin". These bugs would never leave an all you can eat buffet just to hang where there is no food.
I topdress the EWC on the plants. The nutrients will be bio available faster in EWC.