The first day of spring (the spring equinox) is coming up soon, and it’s definitely feeling like winter is on its way out in my corner of the world. I’ve been seeing crocuses and irises in bloom, and even daffodils are almost ready to bust their bright, happy little faces out, so I’m excited to plant flowers and veggies outside soon. But the increased light affects indoor plant life, too. Did you know that your houseplants could really benefit from some spring cleaning and extra care? Houseplants clean the very air we breathe, so the least we can do is return the favor. Here are some ways to help your indoor plants get the most out of the new growing season.
1. Inspect for problems
Check whether your plants look healthy overall. Even if they don’t have serious problems yet, it’s worth it to do an inspection and head off any issues before they get worse. Are the leaves all green and intact? Are there roots poking out of the pot? Does the plant look leggy (aka overextended, floppy, or spindly), or is there evidence of potential pest infestations like webs, holes, spots, or actual bugs? These are all things that can be dealt with, but first you’ve got to face them.
2. Dust and wash
Let’s start with literal cleaning. Dirty, dusty leaves don’t look as pretty as clean ones, but they’re also bad for the health of the plant. Dust blocks light collection (photosynthesis), and gas exchange. Plants breathe through their leaves, and it’s much more difficult to breathe if your lungs are coated in dust. Cleaning can be as simple as wiping leaves with a damp cloth, sponge, or paper towel, and you can dilute a drop or two of dish soap in water to wash down extra-dirty leaves. Most plants, aside from cacti, African violets, or succulents, would also benefit from a shower with room-temperature water. If your plant does have a pest infestation, removal by cleaning with soap and water can often make a dent in the problem.
Fuzzy plants like African violets also need cleaning, but they’re a little trickier because getting the leaves wet is bad for them. You can gently wipe them down with an old, soft toothbrush, a craft brush, or even one of their own broken off leaves.
3. Treat bugs
Warm, dry indoor air makes plants more susceptible to many pests, so look carefully for evidence of bug infestations. This may not look like what you expect, meaning that you may not actually see any bugs themselves. They can be hidden or camouflaged, or so tiny that they’re very easy to overlook. If your plant is unhealthy or damaged, check for any webs, which can be evidence of spider mites, or what look like tiny bits of cotton, which can mean your plant has mealy bugs. The first time I saw scale insects I thought they were just part of the plant, because the immobile, brown bumps looked like part of the branch.
If you find that your plant has bugs, don’t panic. Put the affected plant in quarantine, away from your other plants, while you treat it. Try to identify the pest, and then treat accordingly. You might want to treat even seemingly unaffected plants as a preventative measure. My favorite cure is a systemic treatment that you add to the soil, which is taken up by the plant leaves and then kills bugs that munch on the leaves. I’ve successfully used this one for mealybugs, though it may not work on spider mites. A neem-oil-based spray, like this one, is a more natural solution that is supposed to be effective on a variety of pests. Neem oil alone is often used as a natural insecticide, plus it adds a lovely sheen to leaves. Dilute 1 tsp of neem oil and 1/2 tsp of liquid dish soap in 1 quart (4 cups) of water, shake to mix, and spray on leaves.
4. Trim, prune, and rotate
The reduced winter light and dry, heated air can be hard on plants, so don’t be too surprised if yours ended up with some dead, wilted, or yellowing leaves. Trim those away with clean garden shears, and also prune away growth that has gotten too leggy. If one side of the plant has been facing towards a window for a while, give it a 1/4 or 1/2 turn to help even out the plant’s shape.
5. Re-pot, or pot up
I always used the term “re-pot” to mean moving a plant to a larger pot, but to real plant experts, that’s “potting up.” Re-potting involves replacing the soil in a pot, and possibly pruning the plant’s roots. Why bother? Soil eventually becomes depleted of nutrients, and compacted, which interferes with a plant’s ability to absorb water properly. Root-bound plants stop growing, and roots may wind around each other, cutting off their ability to absorb water and nutrients. Signs that your plant needs to be re-potted or potted up are roots growing out of the drain hole or sticking out of the top of the pot, or soil that dries out quickly or doesn’t absorb water. I realized that one of my plants needed a change after noticing that it had become much more difficult to keep it watered, and discovered very crowded roots when I went to pot-up. Here’s a simple guide to re-potting, and a more in-depth one with root-trimming instructions. Late spring or early summer, around Father’s Day, is generally the best time to do this.
If you’re re-potting or potting up, this may be a good opportunity to divide a plant into multiple pots. You’ll get more plants, for free, plus more room for the original plant, so what’s not to like? In some cases a plant may produce plantlets that look like mini version of the parent plant (like spiderettes, from spider plants), but offshoots from other plants may grow around the base of the main plant. Some plants just put out additional stalks, which can be separated with a sharp knife and potted. Cuttings can often be rooted in water or soil, so if you want more plants, save trimmings from pruning.
Your plants need nutrients to help them grow, so unless you’ve just re-potted, spring is the best time to start fertilizing. Most potting mix includes fertilizer, so wait about 6 weeks after re-potting to start fertilizing. I like to use a diluted water-soluble fertilizer, like this one. To avoid burning the roots, water the plant before applying fertilizer.