All of my orchids (and other houseplants) have been eating nothing but water out of my aquarium(s).
Come the end of February, my orchid hobby will officially be 1 year.
I have collected 19 orchids. So far I've had one casualty (a Phal lowii that was in sad shape to start with) and 5 bloomings-- and right now 6 more are spiking.
All are planted in Hydroton in S/H pots. Most of them are sitting on seedling heat mats, in a north-facing sliding glass doorway under supplemental T5 lighting.
The aquarium water has been supplied from my roomie's un-planted 30 gallon tank, inhabited by a few (and always fewer) very small goldfish, one 8" pleco, and one big fat mean-tempered (can you blame him, in a tank that small??) 10" Red Devil.
I am currently planning a much larger, automated system with actual plumbing. I'd like to hook up my houseplants-- and maybe grow some actual edible foodstuffs as well.
The more I research aquaponics, the more gobsmacked I am that we aren't GROWING OUR FOOD THIS WAY. Seriously. Screw orchids-- this concept really should be overhauling a good portion of the whole damned agricultural industry. It's huge.
AQUAPONICS:
Fish (and worms, and bacteria) poo in water.
Poo-water feeds the plants.
Plants clean the water for the fish.
Never fertilize the plants.
Never clean the fish filter.
You can eat the plants. Hell, eat the fish too while you're at it.
That's the simplified breakdown. Now, maybe you can throw in some supplemental iron or potassium if you really feel like it, and you should probably use some calcium or some such and buffer the pH, but these are minor adjustments. And maybe some kind of sediment might kinda sorta build up in the system somewhere-- but a good number of people have been running their home systems like this for YEARS without need for any major cleanup. Don't even need to dig up the roots when you harvest edible plants; just let the worms deal with it, and there you go.
Whole thing sounds bizarrely way too easy and good to be true. Of course it helps if you already know how to care for fish-- keeping them alive is the touchiest part of the whole operation. Do that and the rest is gravy. Blows my mind, sounds crazy.
But there it is. My orchids are
blooming.
Semi, nothin. I'm gonna go whole hog on this thing!
It's only 1 year so far, of course. Remains to be seen if any major salt buildup issues or nutrition deficits will surface. Stay tuned.