This mans cabbage grows 2 times faster than mine. My plants have been growing outside for a month they were 3" tall. He is wearing a jacket it must be cold where he lives. I think our cold spring weather is why my plants grow slow outside. Maybe his soil is better than mine. Great idea to grow 27 cabbage, if I could grow 3 cabbage it would be great. My cabbage plants all died, maybe plants don't like cold rain every day for a month, maybe I try again Sept 1st. We will be having 90°f temperatures in another 30 days. It is 35°f and frost here this morning.
Watch the video
https://www.youtube.com/watch?v=ctGNlcH_Oig
Where he lives the seasons are reversed from the northern Hemisphere. Summer would be in December and Winter in June. Cabbages would be grown in his winter months since it is probably frost free. It is a neat idea though to grow it vertically in containers. I don't know how he got such big cabbages out of a small container. He must spend a lot of time watering when it doesn't rain.