Which vegetable grows from 1 kg to 16,000 kg in 4 weeks?

Two schools are getting a green makeover.
In Vietnam, have a look at this green-roofed kindergarten!

-And in Williamsburg, P.S. 84 is getting a hydroponic rooftop greenhouse.

-Lastly, check out this Israeli firm and their high-tech system which produces Khai-nam. Seems the food tastes pretty good and grows, according to their youtube video, from 1 kg to 16,000 kg in 4 weeks!! Can this be real???