When should I plant?

Alright so I'm starting out with my first two plants, germinated them for about a week and today I put them in plastic cups. Since this is my first time and I have nothing to lose I want to experiment so in one cup I mixed the soil with some miracle gro food nutrient stuff (forgot what the product was actually called) and the other one I didn't put any. Now that I've planted the seeds (1) how long should they remain in the cup before I plant them into the ground. (2) and should there be a difference in the watering and the amount of sunlight they get in this phase as opposed to when they're in the ground. This is my first post on this website and I hope it made sense cause I'm a bit high at the moment.

depends on how long before they can go outside. a few weeks will give you fair to good roots. water when very dry both inside and out. I do 24/0 before I move outside. Hope this helped a little.