Now that summer has “officially” concluded with the celebration of Labor Day, it is time to turn attentions further to preparing for the oncoming winter. There’s lots to do outside — seeding the lawn, testing soil, composting, cleaning up the summer garden, sowing the fall garden. But there’s also plenty to do for indoor gardening.
While most of my gardening pursuits are concentrated in the out-of-doors, growing produce, useful plants and the odd snack for pollinators, I do also take pride in my indoor plants. Chief among the collection are African violets and a close relative called cape primrose (or often referred to by its Latin genus name Streptocarpus). But there are several different species of orchids, cacti, Thanksgiving and Christmas cacti (thanks to starts from loyal readers), and ginger (yes, real, edible ginger). You can check out more pictures of my violets, orchids, and other plants on my Facebook page (Garden Guru John Porter) and on this webpage.
Everything but the African violets and the orchids that are blooming (there are two at the moment) live outside during the summer and will need to be prepped for the short journey back indoors before the frost comes. The indoor plants will also need to be prepped for the long winter ahead.
The way I see it, unless you have lots of really good light in your house, most houseplants really just survive the winter — they don’t really thrive. To keep your plants healthy, you’ll want to prepare them as well as possible for the upcoming winter.
The first task for indoor plants is repotting. This is something that many people don’t really think of on an annual basis, but it really can help in improving overall plant health and growth. If you think about it, a plant out in the garden has access to a large amount of nutrient-filled soil that we further enrich with compost, mulch and more. Mother Nature even provides more (albeit minute amounts) of nutrients in dust and soil that blows in, leaves and debris that fall to the ground and maybe even in the rain.
Providing fresh, new soil for potted plants on an annual (or semi-annual basis, depending on the plant) can go a long way to getting the best growth out of a plant. Sure, there are fertilizers made specially for houseplants (with lower salt levels to reduce salt burn and “crust” on the pots), but those don’t often contain all of the micronutrients that plants need. Repotting into fresh soil, or even top dressing a potted plant with new soil if the level has sunk, can infuse a fresh supply of nutrients to a plant.
Repotting also provides more room for roots that may have filled up the pots. If the plant has grown to fill its current pot, you’ll want to step up to the next size of pot when you repot. You don’t want to go too big and plant a small plant in a large pot — you usually only step the size up an inch or two per repotting.
And when you repot, don’t be afraid to correct “container habit” by ripping roots apart. Many folks are afraid to damage any plant root, but ripping the root ball into quarters will actually stimulate new growth, and also correct roots that start circling the pot.
As for the plants that live outside for the summer, you’ll also want to give them a thorough inspection and cleaning before bringing them back inside. Pests are much easier to control when the plants are outside and are much easier to spread indoors. Checking for, and controlling, common insects such as scale, aphids, and mealy worms should be done before plants are brought indoors. You’ll also want to check for common diseases such as downy and powdery mildew.
It isn’t just plant pests you’ll want to check for. I’ve heard stories from folks who brought all kinds of hitchhikers indoors that were living in or on plants and pots. Those unexpected guests include a whole colony of ants, spiders and a toad that hibernated most of winter only to start croaking when the plant was moved closer to the heat source. You’ll want to make sure you don’t bring any such surprises into the house.
As for fertilizing, most houseplants don’t require fertilizing when they aren’t actively growing, so giving them a last dose in September or October should be sufficient before the off season. Some plants, though, such as African violets and the Thanksgiving/Christmas cacti, are still growing — so a little fertilizer in the winter is okay.