Begonias are some of the most popular flowering plants for gardens and containers With their showy blooms and attractive foliage, it’s no wonder why But knowing the optimal time to move them from indoors to outside is key to helping them thrive. In this article, we’ll explore when to transplant begonias outdoors based on your climate.
There are over 1,800 species of begonias that originate from tropical and subtropical regions worldwide. They come in a diverse range of sizes, leaf shapes, and flower colors. The major types of begonias include:
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Tuberous begonias – Grown for their large, showy blooms in bright colors like pink, red, orange, yellow, and white. They grow from tubers and are often treated as annuals
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Wax begonias – Also called fibrous-rooted begonias. They have smaller flowers but bloom prolifically. Great in beds and containers.
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Hardy begonias – A few cold-tolerant varieties like Begonia grandis that can withstand chillier climates and overwinter outside in sheltered spots.
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Foliage begonias – Prized for their spectacular ornamental leaves rather than flowers. Includes rex begonias and cane begonias. Excellent houseplants.
Determining When to Move Begonias Outdoors
Begonias thrive in warm conditions and are quickly damaged by frost or freezing. Planting them outside requires waiting until all risk of frost has passed.
As a general guideline, begonias can be moved outdoors around 1-2 weeks after your area’s average last spring frost date. But closely monitor the weather forecast for freezes before transplanting.
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In USDA zones 8-10, plant out as early as February/March once temperatures have stabilized.
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In zones 5-6, wait until early May after the last expected frost.
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In cooler zones 3-4, transplant in late May when lows stay above 50°F.
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Only plant after several days in a row of temperatures above 40°F.
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Be ready to protect newly planted begonias with cloches or fabric row covers if a late frost threatens.
Transitioning Begonias from Indoors to Outdoors
To ensure begonias adjust smoothly when moving outside, they need a period of “hardening off”. This toughens them up before exposure to full sun, wind, and other elements.
Tips for hardening off:
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Start 1-2 weeks before transplanting.
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Move pots into partial shade for a few hours, bringing them back inside for the night.
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Slowly increase outdoor time over 7-10 days.
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Introduce to direct sunlight for just 1-2 hours in the last few days.
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Avoid hardening off on extremely hot, cold, or windy days.
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Reduce watering but don’t let plants severely wilt.
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Only plant outdoors after 7-10 days of gradual hardening off.
Choosing the Best Outdoor Location
When selecting where to place your begonias, keep these factors in mind:
Sunlight
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Most begonias grow best in partial shade or dappled sunlight.
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Variegated varieties appreciate some early morning sun to bring out leaf colors.
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Cane begonias and a few others can take some direct sun but need afternoon shade.
Soil Conditions
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Begonias thrive in organically rich, slightly acidic, well-draining soil. Add compost if needed.
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Improve drainage in heavy, clay-like soils by mixing in materials like peat moss.
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Test pH and amend with sulfur if too alkaline.
Air Circulation
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Allow for good airflow to prevent fungal diseases. Space plants adequately.
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Avoid enclosed, humid locations like against walls or under eaves.
Wind Protection
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Shelter from strong winds that can damage delicate stems and leaves.
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Site them near fencing, shrubs or other structures that block wind.
Planting Begonias in the Garden
When planting begonias in beds or borders:
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Dig holes the same depth as the rootball and 2-3 times wider.
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Gently loosen any rootbound roots and place in the hole.
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Backfill with native soil, firming it around the roots.
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Water thoroughly after planting to settle the soil.
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Space begonias 6-12 inches apart depending on mature size.
Caring for Begonias Outdoors
To keep begonias thriving outdoors:
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Water whenever the top inch of soil dries out. Avoid wetting foliage at night.
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Fertilize every 2-3 weeks during active growth with a balanced, water-soluble plant food.
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Remove spent blooms and dying leaves to encourage new growth.
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Stake taller varieties to prevent damage from wind/rain.
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Watch for pests like slugs and snails. Remove by hand or use iron phosphate baits if needed.
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In cold climates, transplant back indoors before the first fall frost, typically around late September or October.
Overwintering Tender Begonia Varieties
While most begonias are not cold hardy, gardeners in cooler areas have a few overwintering strategies:
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Dig up and store tuberous begonia tubers in a cool, dry spot over winter before replanting in spring.
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Take cuttings from wax and other types to propagate new plants indoors under grow lights over winter.
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Bring potted begonias indoors to a sunny window before frost hits. Reduce water and fertilizer until spring.
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In zones 8-10, hardy begonias like Begonia grandis can be left in the ground heavily mulched over winter.
Key Takeaways on Outdoor Begonia Care
Follow these tips to move your begonias outside successfully:
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Transplant after the last average frost once temperatures have stabilized above 50°F.
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Harden off plants slowly over 7-10 days before moving outside.
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Select a partially shaded spot with rich, well-draining soil and wind protection.
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Water and fertilize regularly during the growing season. Move non-hardy plants back inside before fall frosts arrive.
With proper planning and care, your begonias will reward you with season-long color and performance. Just be patient and avoid setting them out too early before the weather has truly warmed up.
How to Plant Tuberous Begonias
If you are planting begonia tubers directly into the garden, start by loosening the soil and digging a shallow hole. Place the tuber in the hole and cover it with no more than about 1″ of soil. If you are starting the tubers indoors, you can plant them in individual pots or in a tray filled with several inches of moist growing mix.
Set the tuber into the hole with the depression facing upward (like a bowl). Learn how to determine which end is up HERE.
If you live in an area with wet spring weather, you can set the tuber at a slight angle, so water doesnt settle in the depression.
Cover the tuber with about 1” of soil and then water lightly to help settle it in place.
Start with a Better Tuber
It’s easy to see differences in quality when you compare two tuberous begonia plants side by side. Larger tubers (as shown on the left) produce bigger plants with more stems and more flowers. Longfield Gardens offers 5/6 cm tubers that grow into large, full plants. Begonia tubers that are ready to plant should feel dense and firm like a potato.
Sun/Shade: Tuberous begonias are sensitive to intense sunlight and should also be protected from extreme heat. They grow best in the filtered light beneath high trees, or in an area that receives about 4 hours of morning or late afternoon sunlight.
Zone: The plants will not survive winter outdoors except in zones 8-11. In cooler climates (zones 3-7), tuberous begonias are usually grown as annuals for flowers from summer through fall. To check your growing zone, use the USDA Hardiness zone map here.
When to Plant: Tuberous begonias will not grow in cold soil. Plant them outdoors in late spring after the soil is warm and all danger of frost has passed. For earlier flowers, the tubers may be started indoors in pots, about 8 weeks before you expect to plant them outdoors. All you need is a pot, some moist growing mix and a warm, sunny location. Start early and your begonias can be in bloom by Memorial Day. Learn more about starting begonias indoors.
Where to Plant: Tuberous begonias require bright light, but not direct sunlight. They grow well in full to partial shade, but may not flower in areas with dense shade and low light. Begonias are ideal container plants for shady gardens, patios, porches and patios. See the range of tuberous begonia flower styles and some container options HERE.
Planting Begonias & Impatiens! // Garden Answer
FAQ
What month is best to plant begonias?
— Begonias are tender bulbs and require protection from frost. For best results, start them off in temporary pots in a greenhouse in March or April to give them a head start. They can then be transplanted outside in May. — Begonia tubers can also be planted directly outside into borders or containers in May.
What is the lowest temperature begonias can tolerate?
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. Begonias can be planted directly in the garden, or in hanging baskets or window boxes.
Do begonias like full sun or shade?
Begonias are tolerant of a range of light conditions, from full sun to shade. In colder climates, plants can tolerate more light. In warm regions, they need protection from hot afternoon sun to prevent leaf scald. Varieties with darker foliage can withstand more light than those with green leaves.
Do begonias do better in pots or in the ground?
Begonias prefer growing in light, rich soil with a good concentration of humus, similar to the makeup of potting soil. So it’s no surprise the plants tend to thrive in containers. Begonias planted in a pot should be spaced 4-6″ apart and with the tubers buried hollow-side up.
When should you plant begonias?
Begonias are bulbous plants of the summer. You can plant your begonias in planter boxes as early as February, but don’t take them out until the risk of spring frosts (the famous Ice Saints) is over. So, wait until mid-May to take them out, or plant the begonias in the garden beds. The begonia is quite slow to start its vegetation period.
Can begonias be left in the ground in winter?
They can be grown in containers and window boxes or as bedding at the front of a shady border. They are usually treated as annuals and discarded at the end of the season. There are also a few hardy begonias that can be left in the ground in winter in very sheltered, warm locations.
How do you grow begonias?
Grow begonias in peat-free, multi-purpose compost in dappled sunshine to partial shade. Plant tubers of tuberous begonias in spring. Only plant begonias outside in May, when no more frosts are forecast. Water regularly and feed every week or so with a high-potash fertiliser such as tomato feed.
Can begonias grow indoors?
In autumn, dig up tuberous begonias and store the tubers in a cool, frost-free spot for winter. Bring fibrous-rooted types indoors over winter, or treat as annuals and throw on the compost heap. Foliage begonias are grown as house plants but can enjoy time outdoors in summer.
When should you start begonia tubers indoors?
The tubers should be started indoors 4-6 weeks before the final frost date. You can purchase begonia tubers from a garden center. They come out in the early spring and you will find them with hosta roots, alocasia tubers, and gladiolas. Plant tubers in a container with drainage.
Do begonias grow well in summer?
Fibrous rooted begonias can be packed quite tightly into mixed summer displays of other bedding plants. Foliage begonias are best grown as house plants, in a bright room but not in strong, direct sunlight. They will enjoy a holiday in the garden in summer, in dappled shade.