Yes, mosquitoes: That’s the most common question I’m asked when I lecture, when people see these photos, above and below, among my slides. “What about mosquitoes?” After that: “How often do you have to change the water?”
Making an “instant” seasonal water garden—meaning no plumbing required—merely requires a watertight vessel, water, and some floating plants to shade the water surface. I top up the liquid as needed during the season, but do not swap it out completely.
Containers can be anything that holds water, including galvanized wash tubs or cattle tanks; earthenware pots with glazing at least on their interior surface (like my big troughs) and no drainage hole; or some other found object.
Level the pot or pots first (use a carpenter’s level), while still empty, and insert shims beneath, such as from an old shingle or pieces of slate, to adjust and stabilize. Once you add water, forget moving the pot if it’s off-kilter.
Waterford Gardens or Pond Plants Online). Salvinia is nice with a slightly coarser texture. If your garden will go in full sun without a full cover of green, consider dyeing the water black with a non-toxic dye to help shade out algae instead (and hide all the underwater plumbing parts).
You can add fish if you like, but I don’t, since they are easy prey for cats, raccoons and the like. The frogs, above, add themselves at my place. Fish or frogs will eat mosquito larvae and mosquitoes, and I have no issue with insects, with my water pots in bright indirect light and covered in floating plants.
One funny note: If the pot is topped up to near the rim, heavy rains will cause overflow—and not just of water but also floating plants, which will likewise go overboard. Though they spread fast and make more, more, more all season in the water, you don’t want your velvety surface of green to go running down the path or into nearby soil, where the thousands of tiny plants would be impossible to recover…trust me, I have tried.
Don’t overfill, or instead cover the pot or scoop the green stuff into a dish and keep inside during big storms.
“‘instant’ water garden: try seasonal troughs” was first posted here