Window boxes are indoor-outdoor gardens. From a prime perch just outside windowpanes, they share good cheer with the neighborhood, while also ensuring up-close enjoyment of plant life from indoors. Jessie LeBaron, a Brooklyn-based landscape designer, creates one-of-a-kind window boxes for her urban clients. She joined me at Peace Tree Farm, an organic wholesale nursery in Kintnersville, Pennsylvania, to demonstrate how to plant a window box.
LeBaron recommends choosing plants that will cohabit peacefully. After all, they’ll be sharing the same soil mix, the same levels of moisture and fertilizer, and the same light exposure, she says. Compatibility is a must. For her demonstration, LeBaron chose a group of sun-loving plants that prefer their soil to be somewhat dry and lean. She started with ghost echeveria, which bears a curved silver spike of orange flowers; Spanish lavender, with lacy, aromatic leaves and tufts of purple flowers; and fuzzy-leafed Doris Taylor echeveria, also with orange flowers.
Make sure your window box comes equipped with holes in the bottom for excess water to drain through. If there are no holes, drill a few. Then cover the bottom of the box with several sheets of newspaper. The paper allows water to drain but stops the soil mix from washing away. Add a few inches of a fast-draining soil mix for succulents—either commercial or homemade. (To make your own potting mix for succulents, blend two gallons of perlite, one gallon of sphagnum peat moss, one gallon of screened compost, and a tablespoon of ground limestone.)
Organize your chosen plants alongside the window box, shuffling and reshuffling until you have a pleasing arrangement. There’s no need to strive for symmetry. Inspired by the randomness of nature, LeBaron prefers compositions that are unconventionally off-kilter. Once you’ve decided on the positioning of plants, remove them from their pots, one at a time, and place them into the planter, starting at one end. Fill around and below each soil ball with more of the potting mix so the plants end up at about the same depth they were in their pots.
Continue transferring the plants into the window box until it is full. To create the crowded look of a full-grown window box, you might need to scrape soil from some of the root balls to wedge them into narrow spaces. That’s OK, LeBaron says—plants tend to be forgiving of rough treatment. Add extra soil mix to fill any voids, and firm it around the plants. Follow up with a light watering—remember, succulents like their soil on the dry side—and place the box in its permanent spot outdoors.
Let the soil dry to the touch before watering thoroughly. Succulent plants won’t suffer if you disappear for the weekend; these denizens of arid climates are less demanding than some moisture-craving annuals. Before frosty weather in fall, bring the box indoors to a sunny south-facing window, or remove the plants and pot them individually.