Introduction
There is a special kind of excitement that comes with planning a shade garden. While many flowering plants crave the intense heat of the midday sun, begonias thrive in the quiet, cooler corners of the yard, offering brilliant colors and lush foliage that last from midsummer right through the first frost. Whether you are looking for the rose-like blooms of tuberous begonias or the unique, swirling patterns of Rex varieties, timing your planting correctly is the secret to a long and successful growing season.
At Longfield Gardens, we want to help you make the most of these versatile tropical beauties by exploring our begonia collection. Knowing exactly when to plant begonias—both indoors for a head start and outdoors once the weather warms—ensures your garden stays vibrant all summer long. This guide is designed for home gardeners who want clear, practical advice on timing, soil preparation, and variety-specific needs.
By understanding the relationship between local frost dates and soil temperature, you can confidently transition these stunning plants into your landscape at the perfect moment. Successful begonia gardening starts with getting the timing right to ensure healthy roots and a spectacular floral display.
The Short Answer: When to Plant Begonias
The most important rule for planting begonias is to wait for the warmth. Because begonias are tropical in origin, they have no tolerance for frost and will struggle in cold, damp soil. For the best results, you should plant begonias outdoors only after the danger of frost has passed and the soil has warmed up.
In most regions, this means waiting until the soil temperature reaches at least 60°F. Additionally, nighttime air temperatures should consistently stay above 50°F. Depending on where you live in the United States, this window typically opens between late April and early June. If you plant too early, the tubers or root systems may sit dormant and become susceptible to rot; waiting for that consistent warmth ensures the plants take off quickly.
Key Takeaway: Always prioritize soil temperature over a specific date on the calendar. If the ground feels cold to the touch, it is worth waiting an extra week or two to ensure your begonias thrive.
Starting Begonia Tubers Indoors
While you can plant begonias directly in the garden once it is warm, many gardeners prefer to start Non-Stop Begonias indoors. This "head start" allows the plants to develop a sturdy root system and several inches of growth before they ever touch the outdoor soil. This technique is especially beneficial in northern climates with shorter growing seasons, as it can result in blooms appearing as early as late June or July.
Why Start Early?
Starting indoors gives you an extra 8 to 12 weeks of growth. Tuberous begonias are somewhat slow to wake up from their winter dormancy. By providing a controlled, warm environment inside your home, you bypass the slow start that often happens in the variable weather of early spring.
Indoor Timing by the Calendar
To calculate your indoor start date, look up the average last frost date for your specific zip code. Count back 8 to 12 weeks from that date. For example, if your last frost is typically in mid-May, you should aim to start your tubers indoors in late February or early March. For a step-by-step walkthrough, see How to Start Tuberous Begonias Indoors.
Setting Up for Success
You do not need a greenhouse to start begonias early. A warm room with indirect light is perfect.
- Containers: Use shallow trays or individual pots with excellent drainage.
- Medium: A light, moist potting mix is ideal.
- Placement: Place the tubers with the indented (hollow) side facing up. They should be just barely covered or tucked into the soil so the tops remain visible until sprouts appear.
- Warmth: Aim for a room temperature between 65°F and 70°F to encourage the first sprouts.
Understanding Your USDA Hardiness Zone
At Longfield Gardens, we use USDA Hardiness Zones to help determine the best shipping and planting windows for your area. Begonias are tender perennials, meaning they can live year-round in frost-free climates (Zones 10 and 11), but in most of the U.S. (Zones 3 through 9), they are grown as annuals or overwintered indoors. Check our Hardiness Zone Map to find your zone.
Shipping and Arrival
We time our shipments to arrive approximately two weeks before the ideal outdoor planting time for your specific zone. This allows you to either start the tubers indoors immediately or keep them in a cool, dry place for a short period until the ground is ready. See our Shipping Information for more details.
Regional Variations
- Southern Zones (8-11): In these warmer regions, you can often plant begonias outdoors as early as March or April. In South Florida, they are even used as cool-season color in the fall.
- Central and Northern Zones (3-7): Patience is a virtue here. Do not be tempted by a few warm days in April. Wait until late May or early June to ensure the "settled" warmth that begonias require.
What to Do Next:
- Identify your USDA Hardiness Zone using a digital map.
- Check your local extension service for the "average last frost date."
- Watch the 10-day weather forecast for consistent nighttime lows above 50°F before moving plants outside.
How Timing Varies by Begonia Type
Not all begonias are created equal. While they all share a love for warmth, different varieties have slightly different needs when it comes to timing and placement. For a quick reference, see Types of Begonias.
Tuberous Begonias
These are the stars of the shade garden, and a classic example is Begonia Upright Double Roseform Pink, known for their massive, rose-like double blooms. Because they grow from a thick, fleshy tuber, they are the most sensitive to cold, wet soil. These are the primary candidates for starting indoors 8–12 weeks early.
Fibrous-Rooted (Wax) Begonias
Commonly used as bedding plants, wax begonias have smaller flowers but very tough, waxy leaves. They are often sold as started "plugs" or small plants in nursery flats. These can usually be planted outdoors slightly earlier than tuberous types, provided there is no risk of frost, as their fibrous root systems establish more quickly. For more general care, see How to Plant and Care for Begonias.
Rex and Rhizomatous Begonias
Grown primarily for their spectacular, multicolored foliage, these varieties are often kept as houseplants year-round. If you plan to move them to the patio for the summer, wait until the humidity is up and the temperatures are firmly tropical (above 60°F at night). They are very sensitive to the dry air and temperature swings of early spring. For a broader look at the family, read All About Begonias.
Cane-Like (Angel Wing) Begonias
These upright growers are prized for both their spotted leaves and cascading flower clusters. Like Rex begonias, they prefer very stable warmth. They can be moved outdoors once the weather is consistently warm, making them perfect "thrillers" for summer container displays.
Site Selection and Soil Preparation
Once you have determined that the timing is right, the next step is choosing the best location. Timing and placement work together; a plant placed in the "right" spot at the "right" time will require much less maintenance.
Sunlight Requirements
Most begonias prefer filtered light or morning sun with afternoon shade. The intense heat of a 2:00 PM sun in July can scorch their delicate leaves. Tuberous begonias, in particular, excel in areas that receive about four hours of morning light. For hanging baskets and porch displays, see our Hanging Begonias. If your garden is very dark, you may see fewer flowers, but varieties like Rex begonias will still provide incredible leaf color.
Drainage is Essential
"Drainage" simply refers to how quickly water moves through the soil. Begonias love moisture, but they cannot stand "wet feet." If a tuber sits in waterlogged soil, it will rot.
- In the ground: If your soil is heavy clay, consider planting in raised beds or amending the soil with compost to loosen the texture.
- In containers: Always ensure your pots have drainage holes. Use a high-quality potting mix rather than garden soil, which is too heavy for pots.
Depth and Spacing: The Quiet Winners
Getting the depth and spacing right is just as important as the timing. For a whole range of upright forms, see Upright Double Begonias.
- For Tubers: Plant them about 1 inch deep. Planting them too deep can delay sprouting and lead to stem rot.
- Spacing: Space begonias 8 to 12 inches apart. This allows for plenty of air circulation, which helps prevent common issues like powdery mildew.
Transitioning Begonias Outdoors (Hardening Off)
If you have started your begonias indoors, you cannot move them directly from a cozy living room to the garden without a transition period. This process is called "hardening off."
Why Hardening Off Matters
Indoor plants are pampered. They haven't had to deal with wind, direct UV rays, or fluctuating temperatures. Moving them abruptly can cause "transplant shock," where the leaves turn white or the plant wilts.
The 7-Day Schedule
- Day 1-2: Place your begonias in a fully shaded, sheltered spot outside for 2–3 hours, then bring them back inside.
- Day 3-4: Increase the time to 5–6 hours. Allow them to experience a small amount of dappled sunlight.
- Day 5-6: Leave them out all day. Bring them in only at night.
- Day 7: If the nighttime temperatures are above 50°F, they are ready to stay out for good and be planted in their permanent home.
Caring for Your Begonias After Planting
Once your begonias are in the ground or their summer pots, your focus shifts from timing to maintenance.
Watering Correctly
The rule for begonias is "deep, then dry." Water the plants thoroughly until water runs out the bottom of the pot or the soil is moist several inches down. Then, wait until the top inch of soil feels dry to the touch before watering again. Avoid getting water directly on the leaves in the evening, as this can encourage fungal growth.
Fertilizing for Blooms
To keep the flower show going, begonias need regular feeding.
- Early Season: Use a balanced, water-soluble fertilizer to help the plant grow plenty of green leaves.
- Mid-to-Late Season: Switch to a fertilizer higher in phosphorus (the middle number on the package) to encourage continuous blooming. Feeding every two weeks is usually sufficient for container plants.
Deadheading and Grooming
Begonias are generally "self-cleaning," meaning the old flowers fall off on their own. However, removing spent blooms and any yellowing leaves helps the plant look its best and keeps air moving through the foliage.
Garden Tip: If your begonias start to look "leggy" or stretched out in midsummer, don't be afraid to pinch back the stems. This encourages the plant to branch out and become bushier.
What to Do When the Season Ends
As autumn approaches, the question of timing returns. Tuberous begonias will go dormant as the days shorten and temperatures drop. To save your tubers for next year, you must act before the first hard freeze.
Watching the Temperatures
A light frost may blacken the leaves but won't usually hurt the tuber. However, a hard freeze (where the ground begins to crust) can destroy the plant. When the foliage begins to yellow in late September or October, start reducing your watering to signal to the plant that it is time for a rest.
Digging and Storing
- Lift: Carefully dig up the tubers, keeping the stems attached.
- Dry: Lay them in a cool, dry, frost-free area for about two weeks until the stems dry up and fall away naturally.
- Clean: Gently brush off any remaining soil.
- Store: Place the tubers in a paper bag or a box filled with peat moss or vermiculite. Store them in a dark, dry place where the temperature stays around 50°F.
Troubleshooting Common Timing Issues
Sometimes, even with the best intentions, things don't go exactly to plan. Here is how to handle the most common timing challenges.
"My begonias aren't sprouting."
If you started your tubers indoors and don't see growth after three weeks, check the temperature and moisture. Tubers need warmth (at least 65°F) to wake up. Also, make sure the soil is damp but not soaking wet. If the soil is too cold or too wet, the tuber may simply stay dormant.
"The leaves are turning yellow or dropping."
This is often a sign of overwatering or a sudden temperature drop. If you recently moved your plants outdoors and a cold snap hit, they may drop a few leaves in protest. Bring them back into a sheltered area until the weather stabilizes.
"I missed the window to start them indoors."
Don't worry! You can still plant begonia tubers directly outdoors in late May or June. They may bloom a few weeks later than those started inside, but they will quickly catch up in the warm summer soil. You can also purchase started plants from a nursery to get an immediate color impact.
Summary of Begonia Planting Steps
Timing your begonias correctly is the foundation of a beautiful shade garden. By respecting their need for warmth and providing a slow transition to the outdoors, you ensure a stress-free experience for both you and your plants.
- Start indoors: 8–12 weeks before the last frost for tuberous varieties.
- Monitor soil: Wait for 60°F soil and 50°F nights before planting outdoors.
- Hardening off: Give indoor plants one week to adjust to outdoor conditions.
- Placement: Choose a spot with morning sun and afternoon shade.
- Care: Water when the soil surface is dry and fertilize every two weeks.
"The beauty of begonias lies in their resilience. Once the weather stays warm, these plants work tirelessly to fill your garden with color, proving that the best things in the garden are often worth the wait."
Conclusion
Begonias are a rewarding choice for any gardener, offering a high-impact display with relatively simple requirements. By focusing on the "right plant in the right place" and paying close attention to the timing of your local seasons, you can enjoy a lush, tropical-looking sanctuary right in your own backyard. For a striking hanging-basket option, see Begonia Hanging Golden Balcony.
Our 100% quality guarantee ensures that your items arrive in prime condition and are true to variety, giving you the best possible start. Whether you are a beginner or a seasoned pro, the journey from a firm, dormant tuber to a cascading basket of blooms is one of the most satisfying experiences in gardening. We invite you to explore our selection and start planning your most colorful shade garden yet.
FAQ
Can I plant begonias in full sun?
While most begonias prefer shade or dappled light, some varieties—particularly wax begonias with bronze foliage—can handle more sun if they are kept consistently moist. However, in most climates, afternoon shade is highly recommended to prevent leaf scorch and ensure the plants don't dry out too quickly.
How do I know which side of the begonia tuber is "up"?
Tuberous begonias have a distinct shape: one side is rounded and the other has a slight indentation or "bowl" shape. Always plant the tuber with the indented, hollow side facing up, as this is where the new stems will emerge. If you are unsure, you can plant the tuber on its side, and the plant will naturally find its way toward the light.
Do begonias need to be deadheaded to keep blooming?
While many modern begonia varieties are self-cleaning and will drop their old flowers naturally, "deadheading" (removing spent blooms) is still beneficial. It keeps the plant looking tidy and prevents old petals from sticking to the leaves, which can sometimes lead to rot or fungal issues in humid weather.
Can I grow begonias as houseplants after the summer ends?
Yes, many varieties, especially Rex and Angel Wing begonias, make excellent houseplants. Before the first frost, bring the pots indoors and place them in a bright spot with indirect light. Tuberous begonias, however, naturally want to go dormant in the winter, so it is usually better to store their tubers and let them rest until spring.
