If you have a shady space where you want to add color, begonias are the perfect choice! Begonias add effortless color in shade gardens, under trees, and in containers on porches and patios. In general, youll find a warm color palette of yellow, red, orange, pink, and white flowers. Begonia plants are typically under 1 foot tall, with loads of colorful flowers up to 4 inches wide. Begonias are generally hardy in zones 9 & 10, and in colder zones (2 – 8), they can be grown as annuals and overwintered indoors to grow year after year.
Begonias are some of the most popular and beautiful flowering plants, prized for their lush foliage and stunning blooms But like all plants, begonias have specific needs when it comes to temperature Knowing what temperatures begonias can tolerate is key to keeping them thriving in your garden or indoor space.
In this comprehensive guide, we’ll explore the ideal temperature range for begonias, factors that affect their tolerance, signs of heat or cold stress, and tips to protect them in extreme weather. Whether you’re a beginner or seasoned gardener, read on to become a begonia temperature expert!
The Ideal Temperature Range for Begonia Growth
Most begonias thrive in warm conditions and are considered tropical or subtropical plants. Here are the optimal temperature ranges:
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Daytime Temperatures 65-75°F (18-24°C) – This is the ideal range for active growth and flowering
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Nighttime Temperatures: 55-65°F (13-18°C) – Cooler nights allow plants to rest. Avoid sustained temps below 55°F (13°C).
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Peak Summer Temps: 75-85°F (24-29°C) – Higher daytime temperatures are tolerated in summer, but avoid extremes.
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Winter Minimum Temp: 55°F (13°C) – In colder months, don’t let temps drop below this threshold.
These ranges represent the “sweet spot” for most begonias. However, factors like variety, environment, and season can shift the scale slightly.
Key Factors That Influence Begonia Temperature Tolerance
Several variables play a role in determining how much heat or cold a begonia can handle:
Begonia Variety
Different types of begonias have adapted to thrive in diverse climates, so their temperature preferences vary:
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Wax begonias are quite hardy and can tolerate more cold.
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Rex begonias don’t tolerate cold temps and need warmer conditions.
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Tuberous begonias need cool periods to initiate flowering.
Know your specific variety’s needs!
Growing Environment
Outdoor begonias deal with fluctuating temperatures, while indoor plants enjoy more stable conditions. Outdoor plants often acclimate to withstand short periods of temperature extremes.
Seasonal Changes
Begonias tolerate higher temps in peak summer and lower temps in winter dormancy. But rapid temperature swings can still be stressful.
Sun Exposure
Too much hot sun can scorch leaves, especially if plants are exposed to full midday sun in summer. Morning sun/afternoon shade is ideal.
Soil Moisture
Well-drained, moist soil helps buffer roots from air temperature changes. Proper watering is key!
Signs of Heat Stress in Begonias
If temperatures creep above the ideal range, begonias will show signs of distress:
- Wilting or drooping leaves
- Leaves yellowing or browning at edges
- Leaf scorching or sunburn
- Leaf drop
- Flower bud drop before blooming
- Slowed growth
If heat stress continues, the plant can decline until leaves and stems die back. Proper care is needed to help begonias cope with heat.
Signs of Cold Stress in Begonias
Chilly temperatures can also damage begonias. Watch for these clues:
- Shriveling or curling leaves
- Leaves turning brown or black (freeze damage)
- Increased leaf drop
- Lessened flowering
- Slow growth
- Rot issues on chilled roots
Prolonged cold exposure can be fatal. Take prompt action to warm your begonias when needed.
Tips to Protect Begonias from Temperature Extremes
With the right strategies, you can help your begonias thrive through heatwaves, cold snaps, and everything in between:
Adjust Sun Exposure
Too much hot sun scorches leaves. Provide shade with screens, awnings, or filtered light indoors.
Water Wisely
Don’t overwater in hot weather, but avoid drought. Proper moisture prevents dehydration.
Increase Humidity
Misting, pebble trays, and humidifiers prevent crispy leaves in dry heat.
Ventilate Indoors
Ensure good airflow and vent stale hot air. Outdoor fans offer cooling breezes.
Insulate Containers
Wrapping pots helps insulate roots from temperature swings.
Provide Shelter
Move plants into garages, greenhouses, etc to protect from cold.
Use Mulch
An organic mulch layer stabilizes soil moisture and temperature.
Monitor Conditions
Use thermometers to catch issues early before damage occurs.
With some planning and adjustments, you can help your begonias thrive through heat waves, cold snaps, and everything in between!
Outdoor Begonia Care Guide by Climate
Caring for begonias in the garden requires understanding your local growing conditions. Here are some climate-specific tips:
Hot and Humid Climates
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Seek afternoon shade to prevent heat stress.
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Mist plants frequently to increase humidity.
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Use lighter, porous potting mixes that retain moisture but still drain.
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Avoid fertilizing during the hottest months.
Hot and Arid Climates
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Shade is essential, especially on south/west sides of homes.
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Amend soil with compost to help retain moisture.
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Use drip irrigation or water early in the day to reduce evaporation.
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Add mulch to cool the soil and reduce water needs.
Temperate Coastal Climates
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Choose sheltered spots protected from wind and salt spray.
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Provide light shade as midday sun can still overheat plants.
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Mist regularly to boost humidity near the ocean.
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Ensure excellent drainage to prevent root rot in damp winters.
Continental or Inland Climates
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Select wind-protected sites like courtyards or along fences/buildings.
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Mulch heavily to keep roots warm in cold periods.
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Move containers together and/or use cold frames in winter.
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Provide humidity via pebble trays as interior areas can be dry.
Indoor Begonia Care Guide by Room
If growing begonias as houseplants, place them in rooms with suitable conditions:
East or West Windows
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Allow bright light without intense afternoon sun.
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Move plants a few feet back from the window if direct sun is too hot.
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Mist frequently as indoor air is often dry.
South Facing Windows
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Filter the light with sheers or position out of direct sun.
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Increase humidity with pebble trays or a humidifier nearby.
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Avoid cold drafts from the window in winter.
North Facing Windows
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Supplement with a grow light as light levels can be too low.
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Keep room temperatures consistently warm (65-75°F).
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Group plants together to boost humidity around them.
Warm and Bright Bathrooms
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The humidity is begonia-friendly. Provide a pebble tray if needed.
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Ensure plants don’t touch cold exterior walls in winter.
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Provide good ventilation to prevent fungal issues.
Final Tips for Begonia Temperature Success
Follow these tips for happy, thriving begonias in any conditions:
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Learn your specific varieties’ needs – some tolerate more extremes than others.
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Acclimate plants slowly to temperature changes instead of shocking them.
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Address issues proactively once you see signs of heat or cold stress.
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Avoid dry air and humidity extremes which worsen heat/cold damage.
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Insulate, shade, and shelter plants from intense sun, wind, and precipitation.
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Monitor both air and soil temperature to get the full picture.
With proper care tuned to your climate, begonias can flourish indoors and out! Pay attention to their needs, adjust as seasons change, and they’ll reward you with nonstop beauty.
Start Indoors For Best Blooms
In zones 2-8, Begonias do best when given a head start indoors so they can develop before being transplanted or moved outside. Start Begonias 8-12 weeks before the last frost in your area.
To help Begonia tubers warm up from their winter dormancy, place in a warm location (about 70°F) with indirect sunlight, preferably an east, west, or south facing window. If you don’t have good natural light, grow lamps can provide the necessary light for growth. Water slightly every few days, or when the soil has dried out. Water around the edges of your tuber, but not directly on it: avoid overwatering or soggy soil, as water can pool in the tuber’s hollow dip and cause rot.
To increase humidity, you can cover pots loosely with a clear plastic bag. Expect to see growth in 3-6 weeks’ time, depending upon your overall growing conditions. (Note: In zones 2-8, if you do not start Begonia tubers ahead of time indoors, you may only see minimal blooms late in the season.)
The photo shows a sprouted begonia tuber. The top side of the tuber has a hollow dip, and the bottom is rounded with roots. Plant with the round side down. The hollow dip is the top, and sometimes it will already be sprouting buds. If the buds are coming up, try not to bump or break them, and carefully place the tuber in the ground.
When & Where to Plant Begonias
Light Requirements: Begonias are classic shade-lovers that are only reliable perennials in zones 9 and 10. Most are grown as annuals in all other zones. Some newer varieties can tolerate direct sun, especially if its morning sun. In cooler areas, begonias can tolerate more sun than in hot climates. Most like bright, dappled light to grow their best.
Soil Conditions: Begonias grow best in light, fertile, well-drained soil. Begonias are very susceptible to root and stem rot when exposed to cold, wet soils, so proper drainage is essential. Choose a light potting soil with extra perlite if available, or create your own mix using equal parts of potting soil, perlite, and peat moss.
Spacing: Begonia tubers should be spaced about 1 foot apart in the garden, but can be planted closer together in hanging baskets and window boxes. For one begonia plant, a 6 inch pot is the smallest recommended size. (See your Begonia bulb package for specific details.)
Planting: In zones 9 and 10, Begonias can be planted immediately outdoors. In colder zones, Starting begonia tubers indoors to give them the head start they need (see above). Then, you can move them outside when the weather warms up, after any danger of frost has passed and nighttime temperatures have stabilized to 45°F or more.
Begonias are very sensitive to frost, cold, and wet weather, so dont hurry to plant them outdoors; they cant survive temperatures below 45°F. Begonias can be planted directly in the garden, or in hanging baskets or window boxes. Move them carefully — their stems can break easily.
Do begonias like sun or shade?
FAQ
What temperature is too cold for begonias?
Begonias are very sensitive to frost, cold, and wet weather, so don’t hurry to plant them outdoors; they can’t survive temperatures below 45°F.
What temperature should begonias be at night?
CLIMATE AND TEMPERATURE
Most begonias like bright, shady areas out of direct midday sun. Good ventilation results in good growth. Optimum temperatures range from 55℉ at night to 85℉ in the day.
How cold can begonias tolerate in pots?
Winter Care For Begonias in Pots
Unless you live in a warm climate where the temperature doesn’t dip below 45 degrees F, your begonias won’t survive outside over the winter months. Move your non-tuberous begonias indoors and treat them as houseplants.
How low can begonias tolerate?
The American Begonia Society considers 55 degrees Fahrenheit the lower end of begonias’ comfort zone, though some hybrids may be more cold-tolerant.Jul 28, 2020
How cold can begonias grow?
Container-grown begonias can tolerate temperatures as low as 50°F (10°C). Begonias planted in the ground can tolerate temperatures as low as 40°F (4.4°C). It’s also important to note that begonias grown in cold climates need protection in the winter.
Are rhizomatous begonias cold tolerant?
Rhizomatous begonias also show relatively good cold tolerance, with some being able to survive temperatures down to about 30°F. Foliage begonias, on the other hand, are the least cold tolerant and are usually kept as houseplants. Their delicate leaves make them susceptible to damage in colder climates.
Why are begonia leaves so cold tolerant?
Leaf Texture and Structure: The texture and structure of begonia leaves play a pivotal role in their cold tolerance. Some species boast thick, waxy leaves that act as natural insulators, providing a protective barrier against the cold. This adaptation minimizes the impact of temperature fluctuations on the plant’s overall health.
How cold can Begonia semperflorens tolerate?
For instance, Begonia semperflorens, also known as Begonia with silver-leafed foliage, can tolerate temperatures as low as 32°F (0°C). On the other hand, Begonia x hybrida is much more sensitive to cold and typically starts to show signs of stress at around 40°F (4°C).
Can begonias survive winter?
These begonias die back to the ground in winter but re-emerge in spring. While most begonias cannot withstand freezing temperatures, there are steps you can take to help acclimate begonias and provide cold protection: Gradually expose begonias to cooler temperatures in fall to harden them off before winter arrives. This toughens the plant tissues.
Should begonias be indoor or outdoor?
Indoor begonias, protected from the elements, can enjoy more consistent temperatures. However, outdoor begonias are susceptible to temperature fluctuations, making it essential to monitor their environment carefully. 4. Soil Moisture: Keeping Roots Happy