What to keep in mind when moving your plants inside with the seasons
If you have one or a collection of houseplants, it can be fun to move them outside in the warmer months, but we need to remember to bring them back inside before it gets too cold for them. When bringing them inside, there are a few things to remember in order to ensure the health of your plants!
You want to bring your houseplants inside in the fall when low temperatures reach about 50 degrees Fahrenheit. When plants are planted in pots above the ground, their roots are more susceptible to the cold temperatures than if they were planted in the ground. Plus, most houseplants are tropical plants, and aren't evolved to tolerate temperatures at that level. You can leave the plants out during the day if you'd like, and just bring them in for the cooler temperatures, or you can bring them in for good when lows start approaching 50 degrees.
An important part of bringing houseplants inside is pest control. You don't want to bring any insects or diseases from the outdoors inside and contaminate your other inside plants (or, to just annoy you). Insects that commonly can come in with houseplants in the fall include fungus gnats, spider mites, aphids, thrips, or grubs that live in the soil. It is important to take care of these pests before you bring the plant inside.
I recommend inspecting the leaves visually to see if you spot any obvious pests. If you do, treat for those pests accordingly with sprays that specifically target that pest. It may take longer before you're wanting to bring that plant inside, so it is smart to be looking at and checking your houseplant as the summer goes to ensure it doesn't have any pests.
If you don't see any obvious pests, I would rinse your plant's leaves with a wet towel or spray it gently with a hose or shower head. This will shake and rinse off any bugs that may be hanging out on the leaves, as well as clear the leaves and pores of any pollen or dust. Then, I would spray your plant's leaves with a gentle spray such as Neem Oil, which will help with almost all pests. This is a preventative spray against many diseases and fungus as well, so it is good to spray on your plant every once in a while.
You also want to watch out for insects in the soil. When you bring in your plants in the fall, check to see if they need to be repotted for the winter. Most houseplants go "dormant" in the winter, meaning not much new growth is put on, and they are in a state of stress due to lack of sunlight. This means you don't want to repot in the middle of winter, so now is a great time to check to see if your plant needs it. If it does, make sure to remove ALL the soil from the roots when you remove it from its current pot and rinse the roots off. Then, give all fresh potting soil for the plant, and your plant will be free of any bugs brought from the old soil. If your plant doesn't need repotting, You'll still want to remove any pests form the soil. The best way I've found to do this is by using diatomaceous earth. It is a white powder that you mix in the top few inches of soil in your pot. This will kill any larvae, grubs, slugs, or anything else living in your soil (including fungus gnat larvae).
Another product that you can use specifically for fungus gnats are sticky traps. These will catch the adult insects flying around while the diatomaceous earth takes care of the eggs. Within a couple weeks, your fungus gnat problem will be gone!
Remember that your plants have been outside all summer, and sometimes they can become shocked by a sudden move or change in conditions. It is a good idea to gradually introduce them to their new spot, having the plant inside for a day, and outside for a (warm) day. Then two, then three, and so forth until it is acclimated. Don't be surprised if your plant has some yellowing leaves during the transition, yellow leaves are normal and are nothing to be worried about unless it is a majority of the leaves.
Good luck with bringing your plants inside, and feel free to reach out to us with questions, we love to help: firstname.lastname@example.org
Keep going and keep growing!