Constructing a freeform tabletop fountain is a lot more craft than science.
Without a recipe, I ventured into the waters of freeform fountains recently. I had four new bowls I wanted to try out and plenty of favorite rocks to show off. Besides, I love how container water gardens help humidify a dry house in the wintertime, and another soothing sound in the house is always welcome.
Find some rocks that you love, add water and a pump to a big bowl, and you've got the makings of a tabletop fountain. You can use rocks that are larger than the container as long as you tilt them slightly to drain back into the bowl.
The first bowl — a beautiful glazed-pottery casserole — is deep enough but, at nine inches, relatively narrow, so there was room only to create a small bubbler; for a fountain you need to have lateral space to build out the "spillway." I piled it full of small stones and colored glass, put a wide thin rock over the plastic tubing from the pump to direct the flow back into the rocks, and let it go at that. Since the pump's reservoir is relatively small, water will need to be added frequently, so I doubt I'll keep that one plugged in very long.
Plants and water fountains don't mix. If you want plants in your fountain, be sure to put the pot into a leakproof container. Alternately, you can put your completed fountain inside a larger container that holds plants and has a drainage hole, but be careful to set the fountain bowl slightly higher than the planting container to make sure that no potting soil accidentally gets brushed into the fountain.
The second bowl was a trial. Although the inside bottom of the bowl was flat, it had two knobby protrusions that kept interfering with the pump housing. I'd fashioned a cover for the pump out of a plastic deli container but it wouldn't sit comfortably over the lumps. If the top of the housing isn't flat, anything you build on top of that is unstable and keeps sliding. After several other trial runs, including a four-inch PVC coupling — I finally found the answer: a water-garden planting pot, the kind with mesh on sides and bottom. It was wide enough to clear the bumps.
The bowl was also very wide and deep — so much so that I ran out of "filler" rocks. Putting a lot of rocks in a large bowl makes it too heavy to move around. The rocks also displace a significant amount of water, so the advantage you're gaining in less-frequent topping off in a big bowl is lost. Some gardeners use small PVC joints — a relatively lightweight but low-volume, sturdy solution. My husband suggested plastic pot scrubbers, and the disk-shaped type did the job. A dressing of rocks on top hid them from view. And they come with a convenient hole in the middle, so I threaded one down on the plastic tubing at the top of the pump housing. I covered it with two thin, wide pieces of rock, and a few assorted pebbles. It was a lightweight way of building more height to the fountain.
Along the way, I learned more about the kind of rocks that you can't use in a water feature. Everything you put in a water fountain needs to be inert; whatever disintegrates could damage the pump. Granite, polished rock, quartz and flagstone are great. Limestone and sandstone are, of course, out. Some favorite composite rocks brought home from my travels felt too grainy to use safely.
There were a lot of other adventures with those four fountains. By the end of the day, I was wet, gritty-kneed and somewhat more educated. But I also had three interesting fountains that, unlike the ready-made fountains, reflected a bit of my personal taste, and, best yet, I'd "dialed" them to the type of water noise I like to hear.
Maybe you'd like to try creating a containerized fountain on your own. Or, skip the pump altogether and fashion a static water garden. And who knows, maybe a beautiful mini water garden would be perfect for someone on a gift list.