don't give up on that plant, I'm growing a Sour Diesel Auto that I had troubles with at the beginning(no money for fert). It didn't get fed til the beginning of week 4. 4 months later and I'm bout to pull 8+ oz from it. I'm finishing it off in the strong summer sun then bringing it back under my mars sp3000. I'm really liking my Mars Sp3000, it's the strongest one I could find without blowing a grand. It doesn't have a wide foot print but its pretty high ppfd for under 500. It's a great light for 2-3 plants in 2-4 gal pots, any bigger and your gonna run out of footprint.
I'd get a bag of bio biz soil or 70/30 coco/perlite, Pure blend pro bloom soil, Cal mag, and transplant that thing. Look into the sp3000, I like mine a lot.
You want direct sunlight, a green house would be nice for pests and humidity but the direct sunlight is freaking magic.