By Margaret Shea, owner Dropseed Nursery
Two of my favorite things are floating in the water and growing native plants–so building an organic swimming pool has been on my wish list for years. We finally finished the project just in time for this year’s swimming season and it is a delight!
We found a pond design that was the perfect fit for both growing native wetland plants and cooling off in the water. This pond combines a deep swimming zone (ours is 8’ deep) with an adjacent shallow planting zone.
Since our soil does not hold water, we used a liner beneath the entire area. The swimming zone is enclosed by a wooden box (ours is 10’x20’) that separates it from the planting zone. Outside of this box is the planting zone–3’ of sand and gravel that slopes towards the swimming area. The wooden box holds the substrate back from the deep area.
Our planting area surrounds the entire pool and varies in depth from 0-1.5’. Ideally you want equal areas for the planting zone and the swimming zone. A perforated pipe is beneath the sand and gravel, and a bubbler circulates water through the plant roots, into the pipe, and back to the pool. The plant roots work together with the substrate to keep the water clean and clear.
The pond is built above grade to prevent run-off from entering the pool (run-off carries nutrients from the soil into the pool and causes algae blooms). This means you have to wait for rainfall to fill the pond–luckily, we have a nearby spring we were able to use to fill the pond more quickly.
It is wonderful to finally have a wet area to plant species like soft rush, lizard’s tail, pickerelweed, rattlebox and blue flag Iris. Blue vervain, foxglove beardtongue, swamp hibiscus, fox sedge, blue lobelia and other species are thriving right at the edge of the pond where they are out of the standing water, but their roots are wet. The plants were put in the ground in May but are already doing their job to keep the water clear. (See the list of botanical names below.)
We are not the only ones enjoying the pool. Tadpoles immediately colonized the pool. It has been fun watching birds drinking from the shallow area and we have a red-eared slider who sometimes basks on a rock between swims.
You can learn more about the process of building one of these ponds on David Pagan Butler’s YouTube channel.
| Common Name | Botanical Name |
| soft rush | Juncus effusus L. |
| lizard’s tail | Saururus cernuus L. |
| pickerelweed | Pontederia cordata L. |
| rattlebox, seedbox | Ludwigia alternifolia |
| blue flag Iris | Iris virginica |
| blue vervain | Verbena hastata |
| foxglove beardtongue | Penstemon digitalis |
| swamp hibiscus | Hibiscus moscheutos |
| fox sedge | Carex vulpinoidea |
| blue lobelia | Lobelia siphilitica L. |
Margaret Shea has a M.S. in ecology from Indiana University and has worked for a number of Kentucky Conservation organizations before starting Dropseed Native Plant Nursery 16 years ago. Margaret’s past employers include The Kentucky State Nature Preserves Commission, The Kentucky Chapter of The Nature Conservancy, and Bernheim Forest.