Simply Put: Parents, It’s Autumn. Do You Know Where Your Houseplants Are?
Those cool autumn nights are upon us, and if you have some of your houseplants outdoors, it’s time to think about bringing them back indoors for the winter. That is, assuming you want to save them. The other option is to leave them outdoors and say “oops” after the first frost and your houseplants take The Big Sleep.
Let There Be Light: Let’s assume that you do want to bring your plants in. In the great outdoors they have been getting a lot more light than they are likely to get in the house. Remember that plants “eat” sun light, it’s where their energy comes from. They respond to higher light conditions both by making more leaves, and also making leaves that are better able to survive in high light conditions. When you bring your houseplant indoors, back into lower light levels, it’s like putting yourself on a bread and water diet after two weeks at the all-U-can-eat dessert buffet on a cruise ship. It’s a starvation diet, and something has to give.
What happens is, the plant withdraws some of the stored foods (starches and sugars) from its older leaves, and the leaves yellow and fall off. It may grow some new leaves at the same time, leaves that are more effective at catching energy in a low light environment. The leaf stems may even bend over time so that the leaves are held pointing down instead of horizontally, so that they are more able to absorb light coming in from the side (windows) than overhead (sun).
To minimize this light shock, begin by moving the plant into a shadier area outdoors for the next few days. It’s still brighter than indoors, but it will help the plant begin the adjustment to inside. When you do put it indoors, put it in a bright spot, which means in front of a window if you have one. (And close to the window, not 10 feet across the room. Light intensity drops very rapidly with distance from the window.)
Bugs: the odds are pretty good that your plant has picked up some insects while outside. We recommend spraying your plants before you bring them in. We have low toxicity and organic products available for this. Oils and soaps and so on. Check with our houseplant department for recommendations. Even if you don’t see anything, the odds are that, indoors in low humidity, you will eventually develop noticeable populations of mites, aphids and other pests if you don’t do a preventive spray on the way in. You probably are also going to bring some thingies in with the soil—pillbugs and earwigs. There isn’t much you can do about these guys. They don’t bother the plants too much. You can do a catch and release if you see them, usually in the saucers when you water.
Watering: as we said above, the plant has been living large and suddenly, the party is over. It likely will require less water than it needed outdoors, so check before you water. If it’s a small pot, lift it. If it’s heavy, it probably doesn’t need water. On big plants, wait until the soil is at least dry to the touch. Some of my houseplants only require water once in two or three weeks, smaller plants, weekly. But you have to check, you can’t just water on a schedule.
Humidity: indoor dry air is tough on plants, but frankly, there isn’t that much you can do. It becomes more of a problem once you start using forced-air heat. If you have a humidifier on your furnace, or a portable humidifier, that helps a lot. Misting is a waste of time. Standing plants on a tray of gravel with water in the gravel (but the pot not sitting in water) might help a little but isn’t going to work wonders.
Fertilizing (Feeding): NO NO NO. Plants eat sunlight. Fertilizer is not food, its minerals. The last thing the plant needs when you’ve taken away its sunlight and reduced its water is a load of fertilizer telling it to GROW GROW GROW. At best, you’ll get some soft spindly growth. At worst, you’ll burn the roots.
Pruning: Cut off dead branches, dead leaves. Do a little shaping, but don’t do anything drastic. Cutting off leaves reduces the amount of stored food the plant has available to it. Any radical pruning should be done in mid-spring when day length and light levels are increasing, or before you put it back outside.
The first month is the hardest. After that, the leaf drop should slow down, and the plant may even start to look perky. Continue to give it bright light, water as needed, and hold back on the fertilizer, and you should have a houseplant that makes it through to next year.
by Larry Hurley, Perennials Specialist