1. Dig a hole large enough for the plastic tub; insert tub (the rim should sit 2 inches below ground level).
2. Place a layer of rocks, then the re-circulating pump inside the tub, running the power cord up toward a grounded outdoor outlet. Cut a piece of PVC pipe that, when inserted into the pump, stops 2 inches below the top of the urn. Cut a large X in the center of the plastic sheet.
3. Arrange sheet loosely inside the tub and over a 1-foot-wide swath of earth. Insert the pipe through the slit in the sheet and into the pump. Lay the pair of 2-by-4s across the hole. Frame a 2-foot-square piece of nylon storm-door screen with strips of 1-by-1, snip a small hole for the pipe, and place the screen over the pipe and 2-by-4s.
4. Drill a hole in the bottom of the urn using the masonry bit. Slip the urn over the pipe and onto the screen; spray insulating foam sealant around the pipe to make it watertight. Add a flow-control valve midway along the pipe to control water pressure.
5. Fill the urn and underground reservoir with water; plug the pump into the outlet, and test. Once you are satisfied with the water flow, cover the screen with pea gravel. Drain, disassemble, and store the urn and pump inside during the winter.
10-gallon plastic tub
475-gallon-per-hour re-circulating pump
1-inch-diameter PVC pipe
4-mil plastic sheet (from a home-supply store)
2 3-foot-long pressure-treated 2x4s
2-foot square piece of nylon storm-door screen
4 1x1 strips of wood
hand drill with masonry bit 1/8 inch larger than pipe
insulating foam sealant
A. urn B. pvc pipe C. flow-control valve D. insulating foam sealant E. screen frame F. 2-by-4 supports G. plastic sheet H. pump I. plastic tub