next years outdoor

hey everyone i also made a post about this in the basic growing section but i didn't have any luck there...should have just posted it here in the first place...anyways i'm currently growing this year for the first time. next year i'm trying to grow about 10 outdoor plants. the garden area is about 8 X 10-12 feet. i need to know would i be able to fit more plants than this in my area? also i'd like to put a little bit of additives into the soil this year (without digging an individual hole for each plant). i also want to start the plants indoors under flos but i'm not sure how to go about it in a precise manner. i know how to start plants but i would like someone who has done this to possibly give a list of materials that i would need to start atleast 10 plants indoors.