That's a great idea! I'll send him with tank water once a week.
I have a soil ball wabi kusa here at the house, but they're really weird at my husband's office about anything that slightly hints at, well... nature. They even have a trimming policy, so that if something exceeds 24" including its pot, they have to deadhead it.
If you make a soil ball and wrap it with burlap or moss it should appear mostly invisible and they'll think its just a moss ball in water.
Other than that you could try filling it with water from a fish tank and changing it out once a week so it has nutrients
Bump: My fern loves to get a sip of tank water once a week! I try to use it for all of my houseplants. I hadn't thought about using it on outdoor planters, but I do remove about 10 gallons + per water change. It usually just goes on the grass, but I will have to start watering the flowers with it when the 1 ft+ of snow melts (not that I'm tired of winter or anything).
The plants on my front porch are growing like crazy since I started watering them with the water I remove during water changes.
I mean not just growth, but colour too.
Bump: I forgot to mention that I am wrapping the rock wool in sphagnum moss. It's kinda ugly on its own.
I read the same thing -- I haven't used the ADA fertilizers, but I do have a whole slew of ferts from that new line by SeaChem (can't remember the name right now). I imagine I can put them in dropper bottles with instructions on them for him.
Legit ADA Wabi-kusa don't contain any soil, they're just some sort of straw and sphagnum moss wrapped around some small stones (or so I've read). ADA makes a fertiliser for WK, Do! Aqua Be Bright. Their marketing says:
"Apply by foliar application with a hand-spray or supply directly to emersion water. Nutrition such as nitrogen, phosphorus, potassium, and trace elements necessary for growing emersed aquatic plants healthfully can be supplied easily."
You could probably make up something similar yourself.
