Late Summer Houseplant Clean Up

A collection of plants sits outside after a rainstorm

by Evin Morrison, Extension Master Gardener
Photos © Evin Morrison

The key to healthy plants is keeping them tidy. But with all the things going on in our lives, especially with busy summer vacations, taking care of our plants can fall by the wayside. However, now is a great time to do clean up and tend those forgotten plants so they have time to acclimate and put on a little more growth before winter dormancy sets in.

Going one plant at a time, do a full once-over to clean up your indoor plants. Here’s an easy checklist:

Mealybugs present on this hoya cultivar.

1. Check for pests

Neglected plants can be magnets for common houseplant pests like spider mites and mealy bugs. First, closely inspect the plant. Look under the leaves and along the stems and petioles. You can use a flashlight and a magnifying glass if you’re having trouble seeing them. Spider mite webs are a big indicator of their presence, but the webs can also look like dust, so make sure you know the difference. No amount of pruning and repotting, or overall pampering will help the plant if you don’t treat the infestation first.

If you find bugs, check out this article for how to treat houseplant pests. Of course, with our current summer weather, you can also place infested plants outdoors in a shady spot. The rainfall, the tropical-feeling humidity, and natural predators will all help clear the pests from your plant with very little work on your part. Nature will take over! However, if you’ve already treated the plant with a chemical pesticide, keep it indoors, and treat it in quarantine. That way the pests won’t spread to your other plants, and you also won’t affect our native pest predators.

2. Prune and tidy

Plant with dried up leaf — This gasteria’s lower leaves dried out after a missed watering.

cutting off dried leaf with scissors — Prune off thoser dried-out leaves!

Plant with yellow leaves — Prune away all the spent leaves.

torn leaf on plant — This leaf was damaged from being in a high traffic area.

With the summer heat, bright sunny windows, and maybe a few missed waterings, it’s totally understandable for your plants to have a few yellowing or dried-up leaves. We may not realize how strong the sun coming in our windows can be, and that often leads to burnt leaves. You can also use this opportunity to remove damaged leaves.

Yellowing leaves can also become present around the base of plants this time of year as the older leaves die, so the plant can use its energy stores to produce new growth at the top. Now is a great time to prune away all the spent leaves, so they aren’t a hiding place for pests, won’t end up rotting (causing more problems later), and because there’s enough time before winter for the plant to replace that growth with new. Removing damaged leaves will improve the look of the plant and ensure that no bacteria make their way into the plant. If you end up with long stems that have mostly defoliated, this is a great time to start propagating. No matter what method you choose, if you propagate cuttings now, you’ll have nice, sizable plants for gifts during the holidays.

3. Repot, but only if needed

Repotting this time of year can be good for your plant for several reasons. First, if your plant has put on a large amount of growth this spring and summer, you might want to give it a little more room so it doesn’t go through the winter in too tight of a pot. Lots of growth above the soil can be a good indicator of lots of roots below the surface. Gently tease the plant from its current pot and check the roots. Root-bound plants should be moved to a pot that’s about 2 inches larger than its current home. If you repot now, there’s still plenty of bright and sunny days ahead and the roots will be able to grow into their new home. Repotting right before winter hits or even after the days have gotten much shorter increases chances of transplant shock. It’s always a good idea to change as few aspects of the plant’s environment at a time.

Plant with dry soil pulling away from sides of plant — This soil has dried out to the point that it is best to replace the soil and repot the plant.

Houseplant root ball lifted above pot — These roots are holding the soil in place but haven’t begun taking over the pot, so this *Rhipsalis* jungle cactus doesn’t need to be repotted.

On the other hand, maybe warmer weather and travel have led to your plants severely drying out. Soil health directly correlates to a plant’s health. If the soil mixture looks crumbly and gray or it’s so dry there’s a gap between the soil and pot, it’s time to revitalize your substrate. There’s a decent chance that by being so dry your soil has become hydrophobic and isn’t holding the water your plant needs to survive. Remove the plant and knock off as much of the old soil as possible. If you’re concerned about pests in the soil or harmful bacteria, wash the pot with soap and water. Mix some compost or worm castings into your new soil for a natural fertilizer boost and repot your plant into the same container. Of course, if the plant was root bound and that led to poor soil quality, you can also use this opportunity to up-pot the plant.

4. Tame the dust

Hopefully, not all your plants need a full overhaul, but even healthy-looking ones can probably use a good cleaning. If rain is forecast, take your plants outside to a patio table for a natural shower. The rainwater will benefit them, while also rinsing off the dust and grime that comes from living inside. Make sure to bring them in before they are hit with harsh, direct sun as they won’t be acclimated to that kind of bright light, which could lead to scorched leaves.

The brown spots on this Philodendron are the result of too much direct sun.

Dusty philodendron leaves — This *Philodendron* `Birkin’ sits close to an air vent and collects quite a bit of dust. Wiping it down with a microfiber cloth and rinsing under a sharp stream of water will help it grow.

Of course, if you prefer to keep them all indoors, using a microfiber towel and a good spray down in the sink or shower is a great— albeit more industrious— option. Giving all your plants a quick wipe down will clear the leaves of anything blocking the sunlight, allowing them a few more months of good chlorophyll production before they go dormant.

hand with glass watering can over houseplants — Water your plants and fertilize if needed,

5. Water and fertilize

Last, once all your plants are clean and back in their homes, give them a good, soaking watering with some fertilizer. Make sure to follow the directions on the fertilizer to avoid overfertilizing. We are reaching the end of the time when plants put on growth and, therefore, are utilizing the fertilizer we give them. While you can fertilize year round, if the plant isn’t actively growing and taking up the nutrients into its root system, then those chemicals can back up in the substrate and throw the soil chemistry out of balance. This will lead to fertilizer burn on your plants. So, between now and our first freezing days, use the opportunity to feed your plants and help them be in the best health.

Houseplant chores can seem daunting, especially as your collection grows, but going one by one and tackling this checklist will ensure that you don’t lose any of your favorite plants before summer ends.