How do you cover potted plants for winter?

As winter approaches, gardeners need to start thinking about protecting their potted plants from cold temperatures and frost. Covering potted plants is an easy and effective way to help them survive the winter months. Here are some tips on how to properly cover potted plants for winter protection.

Why should you cover potted plants in winter?

Outdoor potted plants are more exposed and vulnerable to winter weather than plants in the ground. Their roots are contained in the pot, so they can freeze more quickly. Plus, cold winds will damage branches and leaves. Covering the plants provides insulation to protect the roots and shield the plant from harsh elements.

Some common reasons for covering potted plants in winter include:

• Prevent root damage – Insulating the roots will keep them at a safe temperature to avoid freezing.
• Protect from frost – Covers block frost from forming on leaves and stems which can kill tender plants.
• Reduce wind damage – Covering cuts down on whipping winds that can desiccate and break branches.
• Retain moisture – Covered pots will not dry out as quickly in cold winter winds.

Covering potted plants for the winter gives them the best chance of surviving until spring and resuming growth when conditions improve.

What types of potted plants need winter protection?

Any potted plant that is not specifically hardy to your climate zone will need some type of winter coverage. Examples include:

• Tropical plants – Bougainvillea, hibiscus, palm trees, etc.
• Annual flowers – Geraniums, petunias, pansies.
• Perennials and shrubs – Rosemary, lavender, Japanese maple.
• Vegetables – Tomato, pepper and herb plants.
• Houseplants – Jade, orchids, ferns moved outside for summer.

Check plant tags or information online to find out the ideal winter hardiness zone rating. Anything above your area’s zone will need cold protection when left outside.

How to prepare potted plants for winter covering

Proper preparation is key to successfully covering and protecting potted plants for winter:

• Wait until plants are dormant – Do not cover plants until they have gone dormant and lost leaves after the first hard frost.
• Remove dead material – Clear away any fallen leaves, stems and debris from the pots.
• Check for pests – Inspect closely and treat for any insects or diseases so they do not overwinter in the covered pots.
• Group together – Arrange all the potted plants close together in a protected spot before covering.
• Water well – Give plants a thorough watering before covering so the soil will stay moist over winter.

Preparing the potted plants properly in fall will help them stay healthy under winter covers.

Where to place covered potted plants

Find an appropriate spot to set up covered potted plants in winter. Ideal locations include:

• Against house walls – The building structure gives insulation and blocks wind.
• Under eaves – Roof overhangs provide some shelter from rain, snow and ice.
• Next to foundations – Concrete retains some heat absorbed during the day to radiate at night.
• On south side – More sun exposure on the south side allows warmth to penetrate covers.
• Sheltered areas – Anywhere protected from prevailing winds, such as courtyards.

Avoid placing covered pots in low spots where cold, moist air pools. Raised beds or surfaces work better. Turn or elevate smaller pots so water does not collect in the saucer under the pot.

Methods for covering potted plants

You can use various methods and materials to cover and insulate potted plants left outdoors for winter:

Burlap

An easy way to cover pots is by wrapping them in burlap. Use breathable, untreated burlap sacks, folding down the top neatly. Leave the bottom of the pots exposed for drainage. Secure with twine if needed. The coarse fibers provide excellent cold protection while still allowing airflow.

Old blankets

For a cheap cover, old blankets or towels work well. Avoid anything too thick or padded that will prevent moisture from penetrating. Cut pieces to size and secure around pots with twine or clips, leaving some slack for insulation. Use clothespins to fasten layers together if needed for extra wind protection.

Cardboard boxes

Corrugated cardboard boxes make decent temporary covers for larger pots. Pick boxes that are slightly wider and taller than the pots. Cut off all flaps so the open box can slide down over pots snugly. Weight down boxes with bricks or stones so they do not blow away.

Bubble wrap

For extra insulation around vulnerable plants, bubble wrap is ideal for wrapping pots before covering. The air bubbles provide an additional buffer against temperature changes. Secure sheets with tape and cover with burlap or blankets.

Straw or leaves

Loosely packed straw or fallen leaves stuffed around potted plants will protect from hard freezes. Keep mulch materials light and fluffy to prevent moisture build up. Surround pots with wire cages to contain the stuffing in place.

Inflatable covers

Inflatable plastic covers for potted plants are available from garden suppliers. They have double walls with air pockets for insulation and resemble small plastic greenhouses. Secure them over plants and use small heaters or string lights if needed for warmth on very cold nights.

Cold frames

Build simple cold frame boxes out of wood, bricks or straw bales to place over pots in winter. Orient the frames for maximum sun exposure. Vent them on sunny days to prevent overheating and condensation buildup inside.

Greenhouses

Move potted plants into an unheated greenhouse or polytunnel structure for winter protection. Provide adequate ventilation and shade pots during sunny midday hours. Small space heaters can give just enough heat to keep plants above freezing.

Caring for covered potted plants

Check covered potted plants regularly over winter and provide care as needed:

• Monitor temperature – Ensure plants do not get too hot on sunny days or too cold on frigid nights.
• Check for condensation – Allow for airflow to reduce moisture dripping inside covers.
• Water when needed – Keep the soil slightly moist but not saturated while plants are dormant.
• Recover after snow – Clear heavy snow immediately to prevent damage to covers and plants.
• Watch for pests – Check for rodents, slugs or insects under covers.

With a little attention over winter, potted plants can be kept in good health until time to uncover them in spring.

When to remove covers from potted plants

As spring approaches, here are signs it is time to take covers off potted plants:

• Daytime temperatures stay above 50°F/10°C.
• Nighttime lows remain above 40°F/4°C.
• Frost advisories have ended in your area.
• Plants show new growth emerging.
• Last spring freeze date has passed locally.

Gradually acclimate uncovered plants to outside conditions again. Start leaving off covers for short periods on warmer days. Provide shade if renewing leaves get sunburned. Resume regular watering as plants come out of dormancy.

Conclusion

Covering potted plants for winter protection can keep them alive until spring. Choose an appropriate cover material and location to shelter plants from cold, winds and precipitation. Provide a few basic care checks while plants are covered. Remove covers gradually as the weather warms again in spring so plants can resume growth. With the right winter preparations, even non-hardy potted plants can make it through cold seasons to flourish again.