Overwintering Begonias in Pots: How to Protect Your Potted Begonias from Frost

Introduction

Overwintering begonias in pots is essential for keeping these tender perennials safe from frost damage and ensuring they bloom beautifully again in spring. While begonias thrive in warm weather, their delicate roots and tubers cannot survive freezing temperatures, making winter care crucial.

Instead of letting your potted begonias die in the cold, you can bring them indoors, store tubers, or keep them in a greenhouse to preserve them for the next season.

In this comprehensive guide, we’ll cover:
✅ The best methods for overwintering begonias in pots
✅ How to store and care for potted begonias indoors
✅ How to protect potted begonias in a greenhouse
✅ Common mistakes to avoid
✅ Expert tips for ensuring strong regrowth in spring

Why Overwinter Potted Begonias?

Begonias in pots are more vulnerable to frost than those planted in the ground because the roots are exposed to colder temperatures. Overwintering ensures:
🌱 Stronger, healthier plants that regrow in spring.
🌺 Bigger, more vibrant blooms next season.
💰 Money savings by keeping your begonias instead of buying new ones.

💡 Tip: If UK temperatures drop below 5°C (41°F), you should move potted begonias indoors or to a sheltered location.

Best Methods for Overwintering Begonias in Pots

1. Bringing Potted Begonias Indoors (Best for Fibrous & Rex Begonias)

✅ Step 1: Move Begonias Indoors Before Frost

Bring pots inside before temperatures drop below 5°C (41°F).

✅ Step 2: Choose a Suitable Location

Place in a cool, bright spot (10-15°C / 50-60°F) such as:
- A windowsill
- A conservatory
- An unheated room or porch

✅ Step 3: Reduce Watering

Water only when the soil is dry—too much moisture can cause root rot.

✅ Step 4: Trim & Maintain Foliage

Remove dead or yellowing leaves to prevent disease.

💡 Tip: Avoid placing begonias near radiators, as dry indoor heat can cause leaf drop.

2. Storing Begonia Tubers for Winter Dormancy (Best for Tuberous Begonias)

✅ Step 1: Cut Back & Remove Foliage

Once the leaves turn yellow and die back, trim stems to 5-10 cm (2-4 inches).

✅ Step 2: Remove Tubers from the Soil

Gently lift tubers out of the pot.
Shake off excess soil but do not wash them.

✅ Step 3: Dry the Tubers for Storage

Let tubers dry for 24-48 hours in a cool, dry place.

✅ Step 4: Store in a Cool, Dark Location

Place tubers in a box filled with dry compost, sawdust, or newspaper layers.
Keep at 5-10°C (41-50°F) in a garage, basement, or shed.
Check monthly for rot or shriveling, misting lightly if too dry.

💡 Tip: Label tubers with variety and color to make spring planting easier.

3. Overwintering Potted Begonias in a Greenhouse (Best for Mild Winters)

✅ Step 1: Move Pots to a Greenhouse

Place potted begonias in a heated greenhouse (above 5°C) for continued growth.
If using an unheated greenhouse, additional insulation is needed.

✅ Step 2: Reduce Watering

Water only once a month—overwatering can lead to root rot.

✅ Step 3: Insulate Pots in Cold Weather

Wrap pots with bubble wrap or fleece for extra warmth.

✅ Step 4: Use a Small Heater if Necessary

If temperatures drop below freezing, use a small greenhouse heater.

💡 Tip: Keep the greenhouse well-ventilated to prevent mold and fungal diseases.

When to Bring Begonias Back Outside in Spring

✅ March – April: Check stored tubers and start watering lightly.
✅ April – May: Pot up tubers indoors for early growth.
✅ After the last frost (typically May): Move potted begonias back outside.

💡 Tip: Apply a slow-release fertilizer when replanting for stronger blooms.

Common Mistakes to Avoid When Overwintering Potted Begonias

🚫 Leaving potted begonias outside in frost – Move them indoors or to a protected area.
🚫 Overwatering dormant tubers – Causes root rot and fungal growth.
🚫 Keeping begonias in a too-warm place – Dormant tubers need a cool, dark space.
🚫 Forgetting to check stored tubers – Inspect monthly for mold, rot, or dehydration.

💡 Tip: If tubers become soft or mushy, discard them and keep only healthy, firm ones.

Final Tips for Successful Overwintering

🌡 Monitor temperatures – Begonias cannot tolerate freezing conditions.
🏡 Choose the right method – Some begonias need lifting, while others can be kept indoors.
💦 Water sparingly – Overwintered begonias need minimal moisture.
🌞 Gradually reintroduce to light – In spring, harden off plants before moving outside.
🌱 Check stored tubers monthly – Prevent rot, mold, or dehydration.

💡 Tip: If overwintering in raised beds, use horticultural fleece for extra warmth.

Conclusion

Overwintering begonias in pots is a simple and highly effective way to protect your plants and ensure bigger, better blooms next year.

By choosing to bring them indoors, store tubers, or use a greenhouse, you can successfully protect your begonias from frost and enjoy healthy, vibrant plants in spring!