Second Time Around: Overwintering Annuals
Many of what are considered "annual" plants can be successfully moved indoors for the winter and then back out again next spring. As simple as it sounds, it is not as easy as simply picking up a planter and bringing it inside. The pleasures of having colorful begonias or geraniums from your patio in your living room all winter make it worth the effort, however.
Here are a few tips for helping your annuals make the transition.
1. Choose healthy plants
No matter how carefully you do it, moving a plant to a different environment is stressful for them, so choose only from your plants that are healthy and vigorous looking. Begonias, geraniums, coleus and impatiens are good candidates. Before you move your plants, make sure you have clean planters and pots with drainage holes, saucers to place under them, as well as plenty of good quality potting soil.
If the plant is in the ground, use a sharp spade to dig around it, trying to get a large part of its root system. Keeping as much of the garden soil in place with the roots as you can, place the plant in a pot and fill with potting mix. Try to keep the potting soil level close to the level of the garden soil. If the plant has been in full sun, place the pot in a shady part of your yard or on a covered patio for a few days. This move will help the plant transition to the lower light levels of indoors.
Watch the weather to determine when to move your plants. The best time to bring plants indoors in the fall varies according to where you live. A good rule of thumb is to move your plants when temperatures are regularly going below 60 degrees F. For specific details for your area, contact your agricultural extension service.
2. Inspect for disease and insects before bringing plants indoors
Once you have your plants potted and pruned, check them for debris, disease, and insects. Remove any dead foliage, damaged leaves or other debris. Prune as needed. Usually plants can be pruned by as much as 50 percent without compromising their health.
Look for moss or mold on the pots and for pesky bugs. To get rid of any hitchhikers that may be hiding in your plant or pot, soak the pot in a larger container of lukewarm water for about 15 minutes. Any pests that were hiding should scramble to the surface for air. If you see a lot of ants, however, you will want to re-plant in a different container because the ants you see will have left behind hundreds of eggs.
Try spraying a solution of a few drops of dish soap and lukewarm water on the plant to ward off other insects. Make sure you spray the underside of the leaves and the stems.
3. Find a good spot for your newly moved plant.
The biggest mistake we make in moving plants indoors is in not helping the plants adjust to the big changes in light and moisture. Many annuals will do fine for a while indoors, but as the dry heat from our furnace increases and the hours of daylight decrease, they can wither and die.
Place plants that require full sun near south-facing windows and place plants that only need partial sun in east- or west-facing windows. If your home does not get much light, or if you have limited window space, consider adding some indoor plant lighting. Check your local nursery for affordable options
Think about grouping your newly moved plants together on non-porous gravel trays to increase humidity. It is important to keep the water level below the top of the gravel with the bottom of the pot not touching the water. Otherwise, the plant could develop root rot. Be sure to use clean gravel for the trays.
In addition, try spraying your plants with water a few times a week to keep them from drying out.
4. Be careful with watering.
Water the annuals thoroughly outside before bringing them inside. Allow excess water to run out of the drainage holes to help flush away any extra salt or fertilizer in the soil. After you bring them inside, though, avoid the tendency to over-water them.
Indoors your plants will not dry out as quickly as they did outside in the summer heat, and their growth rate will be slower with less light. Therefore, make sure the soil is dry to the touch before watering and then when you do water, try to dampen the entire root zone.
5. Fertilize and prune as needed as spring approaches.
In late winter when the days start to lengthen, your annuals will begin to grow more noticeably. You may want to use a light amount of fertilizer at this time. Some plants that have been moved indoors look a bit stretched and thin by now. If so, it's a good time to prune them back. Not only will the plant look better, but the pruning will encourage new growth.
Just like you would with annuals purchased from a nursery in early spring, you should gradually introduce your plants to the cooler temperatures and increasing light outside. When the danger of frost has passed and nighttime temperatures are back in the 60s, you can let them stay outside for the rest of the warm weather season.
There is something very satisfying about successfully overwintering annuals. When you help your plants transition through the seasons, it can help make the transition brighter for you, the gardener, as well. Having a bit of the beauty of spring and summer in your home throughout the colder months is very gratifying as well. Feel free to experiment with these tips to see what works best in your climate and with your home. Good luck!