I put most of my houseplants outdoors for the summer. I calculate that it’s like giving them a summer vacation, since outside they receive more light, bountiful rains and abundant air movement, something impossible to imitate indoors. But it is true that, before I move them back indoors before winter, I have to give them a thorough cleaning so as not to bring unwanted insects indoors at the same time. I realize that many people simply do not appreciate the latter step and thus prefer to keep their plants indoors all year. It’s a personal choice and I respect that.
But even if you prefer to keep your houseplants indoors in the summer, it may be worthwhile putting them outside just once, on a rainy day. Rain cleans their foliage, removing dust and other contaminants that can block the stomata and prevent them from breathing properly. Also, it helps rid the plant of spider mites, so common on indoor plants kept indoors year round. Finally rain helps leach the soil of the plant of its contaminants.
After the rain, however, you have bring the plant back indoors before the clouds disperse, as direct sunlight can cause leaf damage on plants not acclimatized to its intensity. And don’t worry about bringing insects indoors: such a short period outside doesn’t give them a chance to find the plant, especially since they are not very active in rainy weather.
Is the African violet an exception?
Many experts will tell you that the African violet (Saintpaulia spp.) Is an exception to this rule, that it won’t tolerate water on its leaves and thus must always stay indoors… but that’s not my experience. As long as I bring the plant in before nightfall and shake it a bit to remove any excess water or dab the leaves with a paper towel before returning it to its place, I find I have no damage whatsoever and the plant even seems enjoy the experience. And rain isn’t tap water and won’t leave stains behind.