When I'm transitioning my tomatoes, peppers and other random assorted vegetables from inside to outside (and then into the ground), I often use milk jugs or self-watering containers made from plastic bottles such as 2L soda pop bottles and I find that the work fairly well. The only problem with the 2L bottles and once the plants become root bound, their roots are exposed to light through the container on the outside layer. But that's easily fixable with paper (put it in the bottle before the dirt), paint or even tape.
I'm not sure exactly to how what a sea of green is, although some one mentioned it in the garden shop to me the other day and I think he was talking about growing marijuana, something I don't know anything about, and do not really care to try (at least, as long as it's illegal in my country), but from what I can picture, the dense canopy might provide enough shade for the roots, so you might not have to light guard the roots.