Oh man... My coffee can hydro experiment is working. I figured it would fail, and was getting ready to toss the seedling into a big tub of dirt and let her grow that way... And she had roots poking out of the bottom of the starter "pot".
...great. now I've gotta figure out a good feed schedule and mix for a coffee can that's a little under half full of feed solution...
.8 grams of megacrop, maybe? We'll see how she reacts and adjust from there.