So, I run a small veggie farm. I have a little pond which is spring and stream fed. Lots of fishies living/pooping in it, supplying lots of nutrients and indicating a healthy supply of dissolved oxegen in the water. So I strap some empty water bottles to a tray of 4'' pots filled with hydroton clay pellets with lettuce planted in them. Details for later, it works! Happy looking lettuce growing quickly, floating out on the sunny pond. My next ambition is to use trays which exploit the abilities of 3-d printing to achieve these qualities: The trays should - have a usable "tray" space of at least 8"x8" - use capillary action to passively move water from the bottom side of the tray to the top side, where plants in soil blocks can absorb it (I want to eliminate the need for hydroton which is quite expensive). - use printed-in ballasts to maintain buoyancy with a 2.5 pound load. At all times the bottom side of the tray should be submerged, while the top side where the soil blocks rest remains above water (e.g. plants should never be submerged). - be able to quickly and easily be linked to create larger floating pads of interconnected trays. A tether point is also desirable. - be easily cleaned for reuse. Roots will probably try to grow into any opening between them and the water, and it will need to be possible to blast these clean with a pressure washer. I know there's a lot going on here. I'm a broke farmer, I can pay for prototyping of models but not for your priceless expertise, ingenuity and charm. Sorry and thanks.