To protect plants' delicate root systems in the winter, choose pots with large volumes, minimize their exposure to dramatic temperature swings and water when temperatures are above freezing. Winter container gardening is tough — you have to protect plants from wind, harsh sunlight and drying out.
Extra pot: Insert your pot into a larger pot for additional protection. Bury: You can plant and pot into the ground (only 2/3 of the way so water can drain away from the pot) and insulate with leaves, straw, or mulch. During freezing temperatures, cover the branches with a floating row cover or a sheet.
Depending on their hardiness, some potted plants will respond to the first frost by going dormant just like garden plants do. However, as the temperature continues to drop, their roots might die unless they are protected.
The key to success with garage storage is that this area is attached to the house but not heated. The garage never goes below 32 degrees but tends to hover in the 40's and low 50's all winter. This keeps the plant dormant but the plants never freeze. Watering is needed, but not too much or too often.
A heated location isn't always necessary. Moving plants to a space like a garden shed or growing plants in a garage will provide enough protection when it gets cold.
Overwintering Dormant Plants
Most dormant plants will drop all of their leaves or die back to the soil level, which is totally normal. Check on it every few weeks, and water it sparingly through the winter. Keep it on the dry side, but never let the soil become bone dry.
Most houseplants are tropicals and prefer temperatures between 65-75°F during the day and about 10 degrees cooler at night. For many plants, temperatures below 50°F can cause problems. Adjust thermostats to cater to your comfort, but remember your plants need some consideration.
With reduced sunlight and dry air from indoor heating, winter isn't a time when your plants will thrive, but, with the right care, they can certainly survive. “Less sunlight typically sparks a plant's natural dormancy,” says Casey Godlove, creative director at PlantShed.
1. In order to overwinter a perennial or shrub in a container outside, it needs to be two zones hardier than the zone you live in. 2. Perennials and shrubs that are in your zone or one colder can be overwintered in an unheated garage, buried in the ground, or transplanted.
When should I wrap my plants for winter? This Old House landscape contractor Roger Cook suggests to start wrapping your plants in November. If your plants are new, be sure to cover them for the first two years. The older your plants get, the sturdier they become in surviving winters.
If it is not going to rain before the freezing temperatures arrive, you should water plants thoroughly. This is because moist ground stays warmer than dry ground. Watering the night before the freeze arrives will insulate the root structure of the grass and plants, decreasing the potential for cold injury.
While it's tempting to carry annual pots indoors for winter, it's often better to take cuttings. Try this with coleus, sweet potato vine (Ipomoea batatas), Impatiens, Alternanthera, Tradescantia, either rhizomatous or cane or wax begonias, and ornamental sages, including Salvia leucantha.
Know Your Plants' Cold Tolerance
Some frost-tender plants need to be covered as soon as the temperature hits 32°F, while others can handle lower temperatures and/or longer freezing periods. You'll need to look up each of your plants to verify its cold tolerance.
WHEN TO BRING PLANTS INSIDE. As a general rule, tender plants should be brought in when nighttime temperatures are below 50 to 55 degrees F, even if they are hardy for your zone. A plant's roots are more exposed when planted in a container versus in the ground.
Bury the pots or bring them inside.
Simply dig a hole and plant the perennial pot and all. This way the soil in the pot will benefit from the temperature-stabilizing mass of the ground soil. Alternatively, bring the pot into an unheated, not-too-bright interior space, such as a garage or cold cellar.
True annuals and plants that we grow as annuals (considered tender perennials in southern regions) cannot survive cold winter temperatures. But there's no need to say farewell to these plants forever! Many “annuals” can be brought inside, even tender plants that need a winter dormancy period.
Avoid watering when temperatures are below 40°F or when sustained freezing temperatures are expected within 24 hours as this water will freeze and not be available to the plants.
Fabric coverings will prevent the freezing air from coming into direct contact with the moisture on the plant while also capturing the heat that is radiating from the ground. Bed sheets or comforters work best for covering large plants and shrubs.
Yes – if you secure the plant properly. Garbage bags work to cover plants and protect from frost, but they must not be allowed to touch the plant's surface. Use stakes and supports to create a tent-like structure over the plant, which will retain warm air. Make sure the trash bag goes all the way to the ground.
A space heater or solar lamps is all you need to keep the garage warm enough for plants to thrive. Keep in mind that the hotter the room is, the more light and water your plants will need. So you only need to keep the room above freezing for your plants to grow.
Cover Plants – Protect plants from all but the hardest freeze (28°F for five hours) by covering them with sheets, towels, blankets, cardboard or a tarp. You can also invert baskets, coolers or any container with a solid bottom over plants. Cover plants before dark to trap warmer air.
Yes, while not a solution for every freezing situation, sprinklers can help protect plants from freezing injury. In his walkthrough of the proper process, Longstroth writes, "Sprinklers used for irrigation do not protect below 23-24 degrees F," noting that in some cases, spraying water can cause more harm to the plant.