Table of Contents
- Introduction
- The Golden Rule for Begonia Timing
- Understanding Your USDA Zone and Local Frost Dates
- How Soil Temperature Affects Begonia Growth
- Starting Begonias Indoors vs. Direct Planting
- Preparing Begonias for Life Outdoors (Hardening Off)
- Selecting the Right Spot for Your Begonias
- Simple Steps for Planting Begonia Tubers
- Ongoing Care for a Season of Color
- How Weather Variations Affect Your Timing
- What to Do When the Season Ends
- Conclusion
- FAQ
Introduction
There is a special kind of excitement that comes with planning a shade garden. While many flowers crave intense direct sun, begonias offer a lush, tropical look that thrives in those cooler, quieter corners of the yard. If you're after a cascading display, Begonia Hanging Pink Balcony is a lovely example.
At Longfield Gardens, we enjoy how these versatile plants bring vibrant color to window boxes, hanging baskets, and garden borders from midsummer all the way through the first frost. Browse our begonia collection to see the tubers available now.
Knowing when to move your begonias outdoors is the most important step in ensuring they grow strong and bloom beautifully. For a head start, see our How to Start Tuberous Begonias Indoors guide.
This guide is designed for home gardeners who want clear, practical advice on timing their begonia planting. We will cover how to check your local weather conditions, the best temperature for soil and air, and how to transition your plants safely from indoors to out. By following a few simple timing rules, you can enjoy a season full of spectacular, rose-like blooms.
The key to success with begonias is waiting for the weather to be consistently warm and stable before letting them call your garden home.
The Golden Rule for Begonia Timing
The most important thing to remember about begonias is that they are warm-weather plants. Unlike pansies or snapdragons, which can handle a bit of a spring chill, begonias need a truly frost-free environment. If you move them outside too early, the cold can stunt their growth or cause the tubers to rot in damp, chilly soil.
The golden rule for planting begonias outside is to wait until the danger of frost has completely passed. In many parts of the United States, this doesn't happen until late spring or even early summer. See our Shipping Information page for shipping details.
You should also pay close attention to nighttime temperatures. Even if the days feel warm and sunny, the nights need to be consistently mild. Begonias are happiest when nighttime temperatures stay above 50°F, and they truly begin to thrive when those nights reach 60°F. If you see a dip in the forecast, it is always better to wait a few more days.
Key Takeaway Begonias need warm air and warm soil. Only move them outdoors when you are certain there will be no more frost and the nights are reliably warm.
Understanding Your USDA Zone and Local Frost Dates
To find the perfect planting window, you first need to know your USDA hardiness zone. This system helps gardeners understand which plants will survive the winter in their area and, more importantly for begonias, when the growing season typically begins. Use our Hardiness Zone Map to find your zone.
Begonias are only perennial (meaning they come back every year on their own) in zones 9 through 11. In most of the country, they are grown as annuals. This means we plant them in the spring, enjoy them all summer, and then either let them go or lift the tubers to store them indoors for the winter.
Knowing your "average last frost date" is your best tool for timing. This is the date when, historically, the last spring frost occurs in your specific zip code. You can find this information through local university extension services or online weather resources. However, remember that "average" is just an estimate. Weather can be unpredictable, and some years are cooler than others.
How Soil Temperature Affects Begonia Growth
We often think about the air temperature when we garden, but for begonias, the soil temperature is just as critical. Begonia tubers are dormant until they feel the warmth of the earth around them. If the soil is below 60°F, the tuber will sit idle. In cold, wet soil, the tuber is much more likely to develop rot before it even has a chance to sprout.
You can check your soil temperature with a simple garden thermometer. Stick the probe about two to three inches into the ground in the spot where you plan to plant. If the reading is consistently 60°F or higher, your begonias will settle in quickly.
If you are planting in containers or raised beds, you have a slight advantage. For more container help, see How to Plant Begonias in Pots.
What to Do Next
- Find your USDA hardiness zone using a local map.
- Look up the average last frost date for your specific zip code.
- Monitor your local ten-day forecast for nighttime lows above 50°F.
- Use a soil thermometer to ensure the ground has reached at least 60°F.
Starting Begonias Indoors vs. Direct Planting
One of the best ways to get a jump on the season is to start your begonia tubers indoors. Because begonias can take several weeks to sprout and even longer to reach their full flowering potential, starting them early inside your home allows you to enjoy blooms much sooner.
Starting Indoors (The Head Start Method)
We recommend starting your tubers indoors about 8 to 12 weeks before your last frost date. This gives the plant plenty of time to develop a strong root system and several sets of leaves. By the time the weather is warm enough to move them outside, you may even have your first flower buds appearing.
To start indoors, you simply need a shallow tray or small pots filled with a high-quality, damp potting mix. Place the tubers with the hollow (indented) side facing up. Cover them lightly with about an inch of soil. Keep them in a warm room with bright, indirect light.
Direct Planting Outdoors
If you live in a region with a very long growing season, or if you prefer a simpler approach, you can plant the tubers directly into the garden once the soil is warm. The downside to this method is that it takes much longer to see flowers. In many northern states, direct-planted begonias might not start blooming until late August.
If you choose direct planting, wait until at least two weeks after the last frost date. This ensures the soil has had enough time to absorb the spring sun and reach that 60°F sweet spot.
Preparing Begonias for Life Outdoors (Hardening Off)
If you have started your begonias indoors, you cannot move them directly from a climate-controlled house to the garden in one day. The transition from a still, indoor environment to the wind, sun, and temperature swings of the outdoors can be a shock to the plant.
This transition period is called "hardening off." It is a simple but vital step that takes about 7 to 10 days. Think of it as a slow introduction to the great outdoors.
- Days 1-2: Place your begonias in a fully shaded, protected spot (like a covered porch) for just two or three hours in the afternoon. Bring them back inside before the evening cool-down.
- Days 3-5: Gradually increase the time they spend outside by two hours each day. Move them to a spot that gets a tiny bit of filtered morning light, but keep them out of the direct afternoon sun.
- Days 6-8: Leave the plants out all day. At this point, they can stay out in the evening as long as the temperature stays above 55°F.
- Days 9-10: If the forecast is clear and warm, let them stay out overnight.
After this process, your begonias will be "tough" enough to handle the garden. Their leaves will have thickened slightly to protect against the wind and light, making them much more resilient.
Key Takeaway Hardening off is the bridge between indoor starting and outdoor success. Taking 10 days to gradually introduce your plants to the elements prevents leaf burn and transplant shock.
Selecting the Right Spot for Your Begonias
Once the timing is right, the next step is choosing the perfect location. Right plant, right place is a rule we live by at Longfield Gardens. For a basket-ready starting point, see the Hanging Begonias collection.
Light Requirements
Most begonias prefer partial shade to full shade. For step-by-step basket planting, read How to Plant Begonias in Hanging Baskets.
If you have a spot that gets about four hours of morning sun followed by afternoon shade, your begonias will likely be very happy. If you need a bit more sun tolerance, Begonia Upright Double Bertini is worth a look.
Soil and Drainage
Begonias need "well-drained" soil. This means that after a heavy rain, the water should soak in quickly rather than leaving a puddle. If your soil is heavy clay and stays wet for a long time, the tubers may rot.
You can improve drainage by mixing in some organic matter, such as compost or finely shredded bark. If you are planting in containers, the Assorted Bold Container for Shade Collection pairs begonias with other shade lovers.
Simple Steps for Planting Begonia Tubers
When the weather is warm and you’ve picked your spot, it is time to plant. For a quick visual refresher, see How to Plant Tuberous Begonias: Which End Is Up?
- Check the Tuber: Ensure the tuber feels firm, like a fresh potato. If it feels mushy or very light and hollow, it may not be viable.
- Identify the Top: Look for the side with a slight bowl-like indentation. This is the top where the stems will grow. The rounded side is the bottom where the roots will emerge.
- Dig the Hole: For garden beds, loosen the soil to a depth of about six inches. Dig a shallow hole.
- Set the Tuber: Place the tuber in the hole with the indented side facing up. If your area is prone to very wet springs, some gardeners tilt the tuber slightly to the side so water doesn't pool in the "bowl" of the tuber.
- Cover and Space: Cover the tuber with no more than one inch of soil. Space your plants about 8 to 12 inches apart to allow for good airflow and room to grow.
- Water Lightly: Give them a small drink of water to settle the soil. Avoid soaking the area until you see the first green sprouts emerging, usually in two to four weeks.
Ongoing Care for a Season of Color
Once your begonias are settled and growing, they are relatively low-maintenance. For a big, nonstop display, Begonia Non Stop Mix - Bulk Offer is a strong bulk option.
Watering Correctly
The goal is to keep the soil evenly moist but not soggy. A good rule of thumb is to stick your finger an inch into the soil; if it feels dry, it is time to water. Avoid getting water directly on the leaves and flowers, as this can encourage mildew or spotting. Instead, aim the water at the base of the plant.
During the hottest parts of the summer, begonias in containers may need water every day. Plants in the ground usually need a deep watering two or three times a week, depending on your rainfall.
Feeding Your Plants
Begonias are "heavy feeders," meaning they use a lot of energy to produce those big, beautiful blooms. We recommend using a balanced, water-soluble fertilizer every two weeks throughout the growing season. This provides the consistent nutrition they need to keep producing new flower buds.
Deadheading and Grooming
Most modern begonias are "self-cleaning," which means the old flowers fall off on their own. However, you can help the plant look its best by occasionally snipping off any spent blooms or yellowing leaves. This keeps the plant’s energy focused on new growth.
Key Takeaway Consistent moisture and regular feeding are the two biggest factors in keeping begonias blooming. Avoid overwatering early on, and then switch to a steady routine once the plant is established.
How Weather Variations Affect Your Timing
Even the best-laid plans can be interrupted by the weather. It is important to stay flexible as you approach your planting date.
If a cold snap occurs after you have already planted your begonias, don't worry. You can protect them by covering them overnight with a frost blanket, an old bedsheet, or even an inverted cardboard box. Just remember to remove the cover as soon as the sun comes up and temperatures rise.
In contrast, if you experience an unusually early heatwave, your young begonias might need a bit of extra shade or more frequent watering. The plants are quite resilient as long as their basic needs for moisture and protection from the scorching sun are met.
What to Do When the Season Ends
As summer turns to fall, your begonias will naturally start to slow down. When the foliage begins to yellow and nighttime temperatures start dipping back into the 40s, it is time to think about the end of the season.
In cold climates, most gardeners treat begonias as annuals and simply compost the plants after the first frost. However, if you have a favorite variety, you can save the tubers for next year.
- Lift the Tubers: After the first light frost kills the top growth, carefully dig up the tubers.
- Dry Them: Cut off the stems, leaving about an inch attached. Let the tubers dry in a warm, shady spot for about a week.
- Store: Shake off any excess soil and place the tubers in a paper bag filled with peat moss or sawdust. Store them in a cool (around 50°F), dark, dry place like a basement or closet until next spring.
This cycle of planting and storing allows you to enjoy the same beautiful plants year after year, making begonias a wonderful investment for your shade garden. Bright varieties like Begonia Upright Double Roseform Yellow are especially eye-catching.
What to Do Next
- Set a calendar reminder for two weeks after your last frost date.
- Prepare your containers with fresh potting mix.
- Ensure you have a balanced fertilizer on hand for the summer.
- Consider where you will store tubers if you plan to overwinter them.
Conclusion
Planting begonias is one of the most rewarding ways to brighten up the shaded parts of your yard. By waiting for the right temperatures and taking the time to harden off your plants, you set the stage for a successful and colorful season. At Longfield Gardens, we believe that gardening should be a source of joy, and getting the timing right is the first step toward a stress-free, beautiful garden.
Remember that while begonias require a bit of patience in the spring, the reward is a summer filled with lush foliage and stunning blooms that last until the very end of the season.
We are here to support you with high-quality tubers and our 100% Quality Guarantee. Happy planting!
Key Takeaway The secret to begonia success is warmth. Wait for frost-free nights and warm soil, and your begonias will reward you with nonstop color all summer long.
FAQ
Can I plant begonias outside if it is still raining a lot?
While begonias love moisture, they do not like sitting in "wet feet." If your spring has been exceptionally rainy and the soil is muddy or waterlogged, it is best to wait until the ground dries out a bit. Planting in soggy, cold soil significantly increases the risk of the tubers rotting before they can grow.
How do I know if the "hollow side" of the tuber is facing up?
Begonia tubers have a distinct shape that looks a bit like a small bowl or a thick coin with a thumbprint in the middle. The side that curves inward (the concave side) is the top. This is where the stems and leaves will emerge. The rounded, smooth side (the convex side) is the bottom where the roots grow.
Will begonias survive a light frost if I forget to bring them in?
A very light, brief frost might only damage the leaves, which the plant can often recover from. However, a hard frost or a long freeze will likely kill the plant and damage the tuber. If a frost is predicted, it is always safest to cover your plants or move containers into a garage or shed for the night.
Do begonias need to be in total shade all day?
Most begonias prefer "dappled" or "filtered" shade rather than deep, dark shade. While they can survive in areas with very little light, they won't produce as many flowers. A spot that gets soft morning light and is protected from the harsh afternoon sun is usually the ideal balance for the best bloom production.