First appeared as an original article in VioletsFun issue #7. Reprinted in numerous other publications.
Providing your plants with just the right amount of light can sometimes be difficult. This is particularly true when growing in (or near) windows, in “natural” light. It’s a rare home that has windows that provide the ideal amount of light for the plants that the homeowner wants to grow. The location of the windows, eaves or porches, adjacent homes and trees, and numerous other factors influence the duration and intensity of the sunlight. This is why the controlled conditions of an artificially lit garden are so desirable and popular. The needs of the plants aren’t compromised by the windows, the climate, or the weather outside.
The windowsill gardener has two choices: adapt the window to the plants or the plants to the window. In a poorly lit window, this usually means providing supplemental artificial light or growing plants requiring little light. For those living in northern latitudes, for example, a north-facing window in the middle of winter is only good for growing non-blooming foliage plants without supplemental light. A south-facing window, particularly during long summer days, poses a different problem. In this case, either the gardener must grow full-sun plants like cacti, diffuse the light, or otherwise provide shade.
Usually, this means placing a sheer curtain, or some other shading material, between the window and the plants, or moving the plants a distance away from the window. Light that’s too bright or hot can be a problem when growing African violets. Violets, like many of their cousins in the gesneriad family, are relatively low-light plants that can be harmed by prolonged exposure to intense sunlight. This is a problem that we faced when we built our glasshouse and began growing under natural light. Before coming up with a solution, our violets suffered–leaves were bleached, brittle, and stiff. In some cases, dried patches of dead leaf tissue appeared as a result of severe “sunburn”.
Our first step, of course, was to place a shade cloth over the roof of the glasshouse, much like placing a sheer curtain in front of the window, to diffuse the sunlight. Even with a cloth providing 60% shade, we found that the light could be too intense for violets in the middle of summer. Our next step was to provide more “living” shade. We would provide more shade to low-light plants like violets by placing higher-light plants between them and the glass. Though we did this for a glasshouse, the same concepts should apply when growing in a window–the only difference being the area of the glass and the number of plants.
We began by growing more basket plants and hanging them from the ceiling of the glasshouse, above the violets on the benches below. This also had the benefit of more fully utilizing our growing space which, being in business, was important. Much of our ceiling is now covered with plants in hanging baskets. Many of them are gesneriads, such as Columnea, Codonanthe, Nematanthus, and Aeschynanthus, to name some. All of these tolerate brighter conditions than do violets. Since the sun slowly moves behind the attached barn during the day, different areas of the glasshouse receive differing amounts of direct sunlight during the day. This means that we also must arrange the baskets accordingly. For example, plants that tolerate more sunlight, like Nematanthus, are hung in the southern end of the glasshouse, while some other gesneriads, like Episcia and Gloxinea, are hung in the opposite end.
Above the aisles of the glasshouse, between benches, hanging baskets is not possible, since they would be too low to walk beneath. We solved this problem by running wires horizontally, from one end of the glasshouse to the other, against the ceiling, above the aisles, like an “overhead trellis”. Here, we allow plants tolerant of higher light, like Passiflora, Jasmine, and Hoya, to vine. We also grow these vines along wires run along the southern side of the glasshouse. Plants like Jasmine are especially useful when grown this way, since they grow rapidly in the summer, producing lots of leaves and shade, and lose many of these leaves in the winter, when days are dark and short. Even better, all of these plants bloom! Even without blooms, though, the vines provide visitors to the glasshouse with a feeling of being “surrounded” by foliage.
Lastly, we grow taller, higher-light plants on the backs of benches, nearest the window. For example, sun loving Dendrobium orchids are placed nearest the window, while orchids preferring less light, like Phalaeonopsis, are placed at the front of the bench, in their shade. Plants that prefer bright light but don’t grow upright because they are weak-stemmed, can be staked or tied to small “trellises”. They can then be grown as a taller, upright, plant.
Though we’ve done this with a glasshouse, all of these things can be done in an overly bright window. Hang baskets above, let vines grow along wires or trellises, and place large, sun-loving, plants nearest the window. Not only will the violets and other shade-loving plants thank you, but you’ll have even more