Plant-growing pond

• Growing water plants is easy. I grow them separately in two tubs, then move some of it into the turtle pond, where it survives until it gets eaten.
• Large tub is a 50 gallon or so cement tub; small tub is just a tub.
• I stock both tubs with mosquito fish in spring to prevent mosquito larvae infestation. Feeder goldfish work as well if your county does not provide vector control for free. I rarely feed those fish.
• I top off the tubs once a week. In summer, I don't do water changes. In winter I do one every couple of months, since plant filtration does not work well.
• Cover is to keep racoons out. They like to wade and dig around in it, especially when water gets scarc in late summer. It mostly works. You can also leave another small tub with water out for the racoons and other animals to use and they might leave the plant tub alone.
• The planters and the cement block borders are to keep the sides of the tubs from breaking/bending too much.
• If you want fancier plant tubs, you can use barrel-halves with pond liner, or build anything form brick/cement/wood and put a liner into it. Most water-gardening books have examples. I just wanted something functional for the small tub and something functional with some aesthetics for the big one.

Or even simpler: