By Stan Barrett, Colorado State University Cooperative Extension Master Gardener, Denver County
If you thought there were no new gardening ideas under the sun, you likely haven't been introduced to trough gardening.
It's a concept that became popular in Britain at the turn of the century when horse troughs were replaced with metal tubs, thus leaving a lot of rectangular stone containers around the landscape.
Creative gardeners saw the potential for using these troughs to grow miniature gardens. Owners of country homes used a collection of planted troughs to define boundaries of vegetable gardens. Now, they are sought after by container gardeners for growing alpines and other small plants.
A technique for making artificial stone troughs was developed in the 1980s. It uses "hypertufa," a mixture of Portland cement, sphagnum peat moss and perlite, reinforced with chicken wire.
Building a hypertufa trough
Two nested cardboard boxes provide a form; the space between the boxes contains the hypertufa.
Finally, to reduce the surface alkalinity, hose down the trough twice a day for a week. Your trough is now ready for planting.
Planting your trough garden
If you build a small trough, such as suggested above, you'll find obvious limits as to what can be planted. To maintain a pleasing scale, consider only small plants. This likely will mean using sun-loving plants because shade-tolerant plants generally are those with larger leaves.
You can chose annuals, herbaceous perennials and alpines. Combining annuals and perennials works well, but mixing in alpines generally does not work well because they usually have very specific water and drainage requirements and therefore need different soil. Remember, your trough garden will need to be watered and fertilized more frequently year-round than an in-ground garden. They also may need protection during the winter, such as mulching with weeds or straw.
If you choose annuals, you'll enjoy a long summer bloom season and by-pass any worries about wintering over. Perennials are available in greater variety than annuals and often feature more interesting foliage when they aren't flowering. You usually can divide them in a year or two, to obtain more stock. Choose hardy varieties so they will overwinter without a lot of care.
To prepare the trough for planting, cover the drainage holes with pieces of fiberglass mesh, such as is used for window screens. Follow this with a one-half-inch layer of pea gravel. Fill with an all-purpose mixture of commercial potting soil, peat moss and sharp sand or perlite, all in equal volumes.
Plant combinations of the following plants that have similar soil, light and moisture requirements.
Photograph courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010