I cut a large head of green cabbage and just left the plant in place. I did not score the stem as you did. I have four little heads now, about twice the size of Brussels sprouts.
It seems to work, though I don't know how much larger these will grow.
Current Dances: salsa (standard/LA), casino, rueda de casino, cumbia Colombiana, bachata, mambo, cha-cha-chá, merengue, reggaetón.
Dances to Learn/Improve: flamenco, tango Argentino, samba, belly dancing, bhangra, danzón, rumba, cumbia Mexicana.
| current weight: 208.0