How to Keep Plants Alive in the Dead of Winter

The winter months can be tough on indoor and outdoor plants alike. Shorter days, colder temperatures, and dry air can all contribute to plant stress and decline. But with some extra care and planning, it is possible to keep your plants thriving all winter long. This comprehensive guide covers everything you need to know to maintain healthy, happy plants even when the weather outside is frightful.

Caring for Indoor Plants in Winter

Keeping indoor plants alive through the winter requires paying close attention to their care needs. Here are some tips for keeping houseplants flourishing when the heating comes on.

Monitor Soil Moisture

Check the soil moisture of your plants frequently, at least once a week. Water whenever the top inch of soil feels dry.
Use your finger, a moisture probe, or a wooden stick to test the soil. Insert into the soil and if it comes out clean, it’s time to water.
When watering, thoroughly drench the soil until water drains from the bottom of the pot. This encourages deeper root growth.
Reduce water needs for plants that enter dormancy in winter like ficus, croton, and schefflera. Allow soil to dry out more between waterings.

Provide the Right Amount of Light

Rotate plants and swap their positions to ensure all receive sufficient light exposure.
Supplement with grow lights if your plants show signs of not getting enough natural light from windows. Look for telltale signs like leggy growth and fewer flowers or leaves.
Keep lights on for 12-16 hours per day, with LED full spectrum bulbs. Position lights 6-12 inches above the plants.

Increase Humidity

Use a humidifier to add moisture to the surrounding air during the drier winter months. Look for models with an auto shut-off and adjustable settings.
Put plants on trays filled with pebbles and water. The evaporating water will increase nearby humidity.
Mist plants frequently with a spray bottle, focusing on the undersides of leaves. Be sure to use room temperature water.
Group plants together to create a denser canopy. More plants in one space creates a mini greenhouse effect.

Avoid Drafts & Temperature Swings

Place plants away from drafty windows, doors, and vents that can expose them to blasts of cold air.
Move plants off the floor or shelves near exterior walls where temperatures fluctuate most.
Keep room temperatures steady between 65-75°F during the day for most houseplants.
Avoid placing plants directly next to heat sources like radiators, fireplaces, and heating vents.

Fertilize Less Often

In winter, scale back on fertilizing to once every 6-8 weeks. Use a balanced diluted liquid fertilizer.
Watch for signs of fertilizer burn like brown leaf tips and margins. Flush the soil by watering thoroughly to wash away excess salts.
Forgetting to fertilize can cause leaf yellowing and plant decline. But less is needed in winter when growth slows.
If repotting, use fresh soil with fertilizer mixed in to provide nutrients for the next few months.

Caring for Outdoor Container Plants

Outdoor plants in containers need some extra protection to survive through harsh winter conditions since their roots are more exposed.

Choose Frost-Tolerant Plants

Select cold-hardy plants that can withstand freezing temps down to your zone’s lowest average temperatures. Some good options include:

Ornamental kale & cabbage
Cyclamen
Decorative grasses
Pansies
Swiss chard
Heather
Stonecrop sedum

Use Insulating Pots

Plastic, wood, or glazed ceramic pots provide more insulation than thin metal or terra cotta containers.
Or wrap your pots with an insulating material like bubble wrap, burlap, or foam plant sleeves.
Place containers on bricks or plant feet to prevent direct contact with cold ground.

Provide Wind Protection

Erect a temporary wind barrier around plants using stakes and burlap.
Place pots near the house foundation or other structures to block prevailing winds.
Avoid exposed areas and reposition containers to more sheltered spots.

Water When Soil Thaws

Check soil moisture by digging into the soil with your finger 1-2 inches deep.
If frozen, do not water. Wait until daytime temperatures thaw the soil and the top layers feel dry before watering again.
Prevent pots from freezing solid by adding insulation like packing peanuts or shredded newspaper around the inside edges.

Use Frost Blankets

Place horticultural fleece or fabric row covers over plants when hard freezes are expected.
Anchor the edges with stones, boards, or soil so the wind doesn’t blow covers away.
Remove during the day to allow light and air circulation and replace at night.

Add Mulch

A 2-4 inch layer of shredded bark, leaves, straw or other organic mulch helps regulate soil temperature and moisture.
Mulch prevents rapid drying during cold winds. Replenish as it decomposes.
Avoid letting mulch pile up against the plant crown which can cause rotting.

Fertilize Sparingly

One balanced, slow-release fertilizer application in late fall is usually sufficient nourishment through winter.
Liquid fertilizers wash away more quickly with heavy rains and watering. Stick to low nitrogen, phosphorus-heavy mixes.
Over-fertilization can damage roots and lead to plant decline when growth is minimal.

Move Plants Indoors

If temperatures in your zone regularly drop below freezing for extended periods, move potted plants into an unheated garage or basement.
Check soil moisture every 2-3 weeks and water lightly if needed. Aim for just enough to keep soil barely moist.
Provide a grow light on a timer to give plants 6-8 hours of supplemental light per day.

Winterizing the Garden

Preparing the outdoor garden properly each fall helps ensure plants survive the winter and return vigorously in spring.

Remove Annuals & Dying Vegetation

Pull out dead or dying annual plants like flowers and vegetables. Discard debris with fungal infections or signs of disease.
Cut back spent perennials, leaving 3-6 inches of stem growth and foliage. Compost or dispose of cuttings.
Clear away fallen leaves and other debris to prevent diseases and allow for air circulation.

Apply Mulch

Spread 2-6 inches of organic mulch like wood chips, leaves, evergreen boughs or straw around beds after the ground freezes.
Mulching insulates plant roots, reduces temperature fluctuations, and prevents desiccation. Reapply as needed.
Avoid piling mulch directly against plant crowns. Leave some breathing space.

Dig or Till Soil

Loosening and turning over garden soil in fall allows water to penetrate deeply and improves drainage.
Dig carefully to avoid damaging shallow feeder roots. Stop digging once soil gets hard to turn over.
Adding organic compost improves winter soil health and provides nutrients for spring growth.

Insulate with Row Covers

Cover overwintering vegetable crops like cabbage, carrots and leeks with horticultural fabric once cold weather arrives.
Weigh down edges securely so covers do not blow away. Fold back on sunny days to allow ventilation when above 40°F.

Plant Cover Crops

Sow cold-tolerant cover crops like rye, wheat, and hairy vetch in empty garden beds.
The root systems prevent soil erosion while the tops protect and add organic material.
In spring, till under plants before they go to seed or spray with an herbicide and add the remains to the soil.
Leave some beds uncovered to allow the freeze/thaw cycle to work the soil naturally.

Protect Trees & Shrubs

Wrap tree trunks with a commercial guard or burlap to prevent sunscald, freeze injury, and rodent damage.
Mound mulch, leaves, or soil around the base of shrubs and roses to insulate roots and crown.
Stake tall or flexible trees and shrubs to brace against strong winds and heavy snow loads which can cause breakage.

Store Tools Properly

Clean all garden tools with soap and water and dry thoroughly before storing for the winter.
Lightly oil metal surfaces to prevent rusting. Wipe away standing water on shovels and spades.
Store tools in a dry location like a garden shed or basement, off the bare ground.

FAQs About Caring for Plants in Winter

What temperature do most houseplants prefer in winter?

Most houseplants grow best with daytime winter temperatures between 65-75°F and around 60°F at night. Avoid drafty spots and extremes under 55°F or over 80°F.

Should I mist my indoor plants in winter?

Light misting can boost humidity levels which tend to plummet indoors in winter. But take care not to overdo it and make leaves excessively wet, which encourages fungal diseases. Always use room temperature water, not cold.

How often should I water my houseplants in winter?

Water whenever the top inch of soil dries out, testing with your finger. This may mean watering every 2-3 weeks for some plants, while cacti and succulents may need only monthly.Reduce water needs for semi-dormant plants like ficus and croton.

What should I do if the soil in my potted plants is frozen solid?

Do not water frozen pots as this will only lead to root rot. Wait until daytime temperatures thaw the soil before watering lightly. Add insulation like packing peanuts around pot edges to help prevent solid freezing.

Is it okay to trim and prune plants in winter?

Most pruning and cutting back of plants should wait until early spring after the last hard frosts. But removing dead stems and foliage anytime helps improve plant health. Prune evergreens like juniper carefully in winter to avoid winter burn.

When should I start hardening off plants for the transition outside in spring?

Begin hardening off seedlings and new plants by setting them outdoors in a sheltered spot for a few hours per day about 1-2 weeks before the expected last spring frost date. Gradually increase their time outside over a week or two.

How do I know if my plants need more humidity in winter?

Signs your plants crave more humidity include dried out leaf tips, brown crispy lower leaves, leaf drop, and a dull or faded appearance. Boost moisture levels around your plants using trays of pebbles, misting, grouping plants together, or getting a humidifier.

What is the best temperature to keep my house at if I have a lot of plants?

The ideal thermostat setting for most houseplants is around 70°F during the day and above 55°F at night during the winter months. Avoid drastic temperature swings and drafts from windows or doors by keeping plants in the most stable area of the home.

Conclusion

Caring for indoor and outdoor plants through the tough winter months requires diligence and attention. But with careful watering, proper light conditions, temperature and humidity control, plant insulation, and other smart practices, you can maintain a thriving indoor jungle and prepare your garden for a vigorous spring. Pay close attention to your plants’ needs, protect them from the elements, and provide nurturing care to keep them healthy even during the dead of winter. With a little effort, your plants will continue flourishing despite short days and cold nights.