I'm not sure what you are asking. Seedlings placed in direct sunlight should certainly get enough light. Some types of seedlings may receive too much light if placed in direct sun. If you place seedlings in a greenhouse under other plants or with a shadecloth on the greenhouse, it will depend on the type of plant and the amount of light allowed to reach the seedlings.

I don't start any seeds indoors, however I do start them in a heated greenhouse - we do not have any extra lighting in there. Right now we only have early, perennial herbs going that do fine with lower light. We will start seeds in two weeks as we get more light, right now there is not enough in my estimation.
I start my veggie seeds outdoors in a cold frame, or under small tents directly over raised beds. I start these as soon as there is enough constant sunshine to warm the beds (mid February usually) and it works well. End of February I start summer veggies in the cold frame.
I never use extra lighting and I never have a problem.

Brandon7
"I'm not sure what you are asking"

Sorry I thought it was clear enough.

"Will the GA sun in zone 7 provide enough sun for seedlings without any extra lighting?"