Found these bowls today and decided to give this a try. They're not real wabi kusas since I didn't have clay around to maintain the dirt ball as an island, so they're really just mini planted bowls. Still very cool for an office desk.
Worked with what I had, did 3 bowls with some dirt/sand out of my balcony planters, and available aquarium plants.
ludwigia glandulosa, ludwigia arcuata, star repens, hc