Seedling Start and Groth

I just started growing last Feb. I live in Hawaii. I have just started my 4th crop in my greenhouse. I am allowed 7 plants with my Medical Card.
I built a beautiful 8'X10" greenhouse with a clear poly roof and special cloth on the sides that lets in 90% of the light but one can not see through it for privacy. Of course, I have made every mistake in the book with growing. I am learning by my mistakes. But need to know more. I order feminized seeds so that I do not have to have more than the allotted plants. Because no sexing is required and I can have at all times 7 pots going. I am allowed only 3 mature plants at one time so I must stager their starts. I use 8 gallon pots. Here is my current problem. It would be nice to start the feminized seed in the 8 gallon pot to bypass a transplant that requires time to get going again. The last time I tried this I germinated the seed via the wet paper towel method. They are fresh seeds and nice little root tails in about 48 hours. When I put it in the 8 gallon

when I put it in the 8 gallon pot, it popped up ok but when nowhere. Do I need to start it in a smaller pot? If so, what medium and nutrients to use. Can I start it in the 8 gallon pot and make it work somehow? I am using House and Garden Van De Zwaan nutrients. I am told that the little starts are too small to add nutrients but it is obvious they need nitrogen. and some type of root enhancer. Any good suggestion out there on how to get started so I do not waste time?

it would be nice if I could start them in the 8 gallon containers so I do not need to have the lag time of a transplant taking hold.