Now that the cool nights of fall are approaching, it's time to begin the annual ritual of preparing houseplants for the end of their summer vacation.
As simple as this task sounds, it's not as easy as picking up your potted fern and moving it from the patio to a corner of the den.
"One must remember that the outdoor environment of summertime is very different compared to the heated indoor environment of winter," says Harold Taylor, a section gardener at Longwood Gardens in Kennett Square, Pennsylvania.
Here are a few tips to consider before moving your plants that will help them survive the move, stay healthy during the winter and enhance your enjoyment of them inside.
When to make the move
Because the climate varies widely across the country, the time to bring houseplants indoors in the fall also varies. As a general rule, Taylor suggests that a good time to make the move is when temperatures regularly dip below 60 degrees F. For specific plants or to determine when nighttime lows in the 50s might consistently occur in your area, contact your local agricultural extension service.
Decide which plants you're going to bring indoors well ahead of moving day. One thing to consider is the health of the plant. If a plant has been struggling to stay alive outdoors, bringing it indoors to low humidity, dry heat and low light levels will increase the stress on it and you. As hard as it may be, it's usually best to put struggling plants in the compost pile.
Give priority to healthy plants and those that have the most sentimental value. If some of your plants have increased in size and are about to burst out of their pots, it's a good idea to buy any re-potting supplies you will need for this well in advance of moving day. Taylor recommends a high-quality potting soil, appropriate containers with drainage holes and appropriately sized plastic saucers to place under the pots to avoid staining hardwood floors or carpets when you water.
Prepare the plants for the move
The first thing to do is to thoroughly check the outside of the pot, the plants and the potting medium. Look for signs of hitchhikers, moss or mold on the pots and unwanted guests such as mealy bugs or spider mites on the foliage or earthworms, snails or ants in the potting mix. Scrub the exterior of dirty pots with a solution of 10 percent household bleach and then hose off the bleach solution. Next, check for hitchhikers that might be hiding in the potting medium. To do this, soak the pot in a tub of lukewarm water for about 15 minutes. Any unwanted pests that have made a home in the soil will scramble to the surface in search of air. Depending on what, if anything, comes out of the pot, you might want to repot the plant — especially if there is an active ant colony. (Ants will leave eggs behind that will eventually hatch.)
If you're repotting the plant, remove the potting medium from the root mass with a spray from the hose, scrub the interior of the pot with a solution of 10 percent household bleach and put a screen or mesh over the drainage hole before re-potting with fresh potting soil. If the roots have filled the pot, repot in a slightly larger pot. Finally, check the foliage for dead or yellowing leaves, remove as needed and prune if shaping is required. Then, several days before bringing the plant indoors, spray the foliage with an insecticidal soap. These soaps are safe for you, your children and your pets.
Prepare the indoor area
Before "moving day," decide where you're going to place each of the plants inside. It's always challenging to find the best place for a particular plant, Taylor says. A guide to doing that, he advises, is to place plants that require full sun near south-facing windows and plants that only need partial sun in an east- or west-facing window. One other option he suggests homeowners consider is to use indoor plant lights, which, he adds, are a popular and affordable solution when you're faced with less-than-ideal locations for houseplants.
You'll also want to avoid areas that might get wintertime drafts from opening and closing doors and heating vents. If you acquired any hanging plants during the spring or summer growing season, install plant ceiling hooks. This is also a good time to purchase plant stands or to build shelving for plants if you're handy, have a lot of plants or live with a plant-loving spouse or partner. As part of your indoor preparation, consider grouping plants together. The plants will appreciate being grouped together on non-porous gravel trays because that will help increase the humidity in the growing area. Keep water in the gravel trays, but take care to ensure that the water is below the top of the gravel so that the bottom of the pot doesn't touch the water. Otherwise, the pot will wick up water into the potting medium and create conditions that are conducive to root rot.
If you have the space, place the plants you're bringing indoors in a separate room from areas where you have other houseplants. This will allow time for signs of hitchhikers you might have missed in your outdoor inspections to show up. If any do, they can be treated at this time.
Avoid transplant shock
The light in many homes is less than the plants will have experienced outdoors. Try to move your plants to the lower light levels of your home in stages to reduce transplant shock, advises Carol Simpson of Ashe Simpson Garden Center in Chamblee, Georgia. Transplant shock typically shows up as yellowing or dropped leaves. However, as the plant adjusts to the indoor light, it will generally replace the leaves it dropped.
Pots won't dry out as fast indoors as they did in the summer heat, and plants will grow more slowly indoors than they did under strong light conditions. Therefore, they don't need as much water in the house as they did on the patio. Make sure the soil is dry to the touch before watering. Succulents will need water less often than foliage plants.
Fertilize according to package instructions, unless the plants were potted in a mix that contains fertilizer. Simpson likes to topdress houseplants with worm castings, which are available at many local nurseries. She advises that homeowners water the castings into the potting mix before bringing the plants indoors. She suggests doing this outside to avoid a potential mess in the house.
If all goes well, in a few months you can begin the move back outdoors after danger of frost has passed in the spring and nighttime temperatures are safely back in the 60s.