Table of Contents
- Introduction
- Understanding the Best Time to Plant
- How to Prepare Your Begonia Tubers
- Starting Begonias Indoors: Step-by-Step
- Moving Begonias to the Garden
- Planting Outdoors: Depth and Spacing
- Water and Fertilizer: The Essentials
- Choosing the Right Begonia Variety
- Maintaining Your Begonias All Season
- Preparing for the End of the Season
- Common Myths and Realistic Expectations
- Why Quality Matters
- Conclusion
- FAQ
Introduction
There is a special kind of excitement that comes with planning a summer garden, and few plants offer as much reward for so little effort as tuberous begonias. These shade-loving stars are famous for their lush, rose-like blooms and vibrant colors that can brighten up even the quietest corners of a yard. If you are looking at a handful of tubers and wondering if the timing is right to get them into the soil, you are in the right place with tuberous begonias. At Longfield Gardens, we want to make sure your gardening experience is as successful and enjoyable as possible.
The answer to whether you can plant your begonia tubers right now depends mostly on your local weather and whether you plan to start them indoors or out. Because begonias are tropical plants, they thrive in warmth and are very sensitive to the cold. If you want to check your growing zone, our Hardiness Zone Map is a handy tool.
The most important thing to remember is that timing beats tricks every time; by matching your planting schedule to your local climate, you ensure your begonias have the best start possible. If you’re ordering from Longfield Gardens, our Shipping Information page explains timing by zone.
Understanding the Best Time to Plant
When deciding if you should plant your begonia tubers today, the first question to ask is where they are going to live for the next few weeks. Tuberous begonias are not fans of the cold, and even a light frost can damage the tender new growth.
Starting Indoors for an Early Jump
If it is still late winter or early spring in your area, you can definitely plant your begonia tubers now—provided you start them indoors. Most gardeners find that starting your begonia tubers indoors about 8 to 12 weeks before the last expected frost date gives the plants a fantastic head start.
By the time the weather warms up outside, your begonias will already have established root systems and several inches of leafy growth. This "pre-starting" method usually results in flowers much earlier in the summer. If you wait until it is warm enough to plant them directly in the garden, you might not see blooms until much later in the season.
Planting Directly Outdoors
If you prefer to plant your tubers directly into garden beds or outdoor containers, you must wait until all danger of frost has passed. A good indicator is the soil temperature; begonias prefer soil that has warmed to at least 60°F. If the ground is still cold and soggy from spring rains, the tubers may sit dormant or, in some cases, struggle to thrive. For more growing advice, see our Tips for Growing Tuberous Begonias.
In most parts of the United States, the outdoor planting window opens in late May or early June. If you live in a warmer climate (Zones 9–11), you can often plant much earlier, but for everyone else, patience is a virtue that leads to much healthier plants.
Key Takeaway: You can plant begonias indoors as early as February or March to get a head start. Only plant them outdoors once the threat of frost is completely gone and the soil feels warm to the touch.
How to Prepare Your Begonia Tubers
Before you put a single tuber in the soil, it helps to know what you are looking at. Begonia tubers look a bit like small, brown, hairy stones or dried bulbs. They have a distinct shape that tells you exactly how they want to be positioned in the dirt.
Identifying the Top and Bottom
One of the most common questions we hear is "which side is up?" Begonia tubers are usually bowl-shaped. One side is rounded (convex), and the other side has a hollow or indented area (concave).
- The Hollow Side: This is the top. This is where the "eyes" or growth points are located.
- The Rounded Side: This is the bottom. This is where the roots will eventually emerge.
If you look closely at the hollow side, you might already see tiny pink or white nubs. These are the sprouts waking up. If your tuber is very flat and you truly cannot tell which side is which, you can plant it on its side, and the plant will naturally figure out which way to grow.
Checking Tuber Health
Healthy tubers should feel firm and heavy for their size. If a tuber feels very light or hollow, it may have dried out too much during storage. If it feels mushy, it has likely been exposed to too much moisture. We take great care at Longfield Gardens to ensure our tubers arrive in prime condition, so you should see firm, healthy specimens ready to grow.
What to do next:
- Inspect your tubers for firm texture and visible "eyes."
- Identify the hollow side (top) and the rounded side (bottom).
- Gather shallow pots or trays if you are starting indoors.
- Prepare a high-quality, well-draining potting mix.
Starting Begonias Indoors: Step-by-Step
Starting your tubers indoors is a rewarding way to pass the time while waiting for spring to arrive. It is a simple process that requires just a bit of space on a bright windowsill or under a basic grow light.
Choosing the Right Container
You don't need deep pots to start begonia tubers. A shallow tray or small individual pots with drainage holes work best. Drainage is the most important factor here; begonias like moisture, but they do not want to sit in water.
The Planting Process
- Fill the container: Use a light, peat-based potting soil. Fill the pot about two-thirds of the way.
- Place the tuber: Set the tuber on the soil surface with the hollow side facing up.
- Cover lightly: Add just enough soil to barely cover the top of the tuber—about half an inch to an inch is plenty. You want the sprouts to be able to reach the light easily.
- Water sparingly: Give the soil a light drink to settle it. Do not soak it.
- Provide warmth: Place the pots in a warm spot (around 65–70°F). You don't need intense light until the sprouts actually break through the soil surface.
Caring for Indoor Sprouts
Once you see green stems poking through, move the pots to a bright location with indirect sunlight. An east-facing window is often perfect. Be careful with south-facing windows, as the direct midday sun can sometimes be too hot for tender young leaves.
Keep the soil consistently moist but never saturated. If the soil stays too wet before the plant has enough leaves to use that water, the tuber can rot. A simple way to check is to stick your finger an inch into the soil; if it feels dry, it is time to water.
"Starting begonias indoors is like a preview of summer. Watching those first pink nubs turn into lush green leaves is the perfect cure for the winter blues."
Moving Begonias to the Garden
Once the weather warms up and your indoor-started begonias are looking full and healthy, it is time to move them to their permanent summer home. However, you cannot move them directly from a cozy indoor room to the Great Outdoors without a little transition period.
Hardening Off
"Hardening off" is just a fancy way of saying "getting the plants used to the wind and sun." Start by placing your pots in a shaded, protected spot outside for a few hours a day. Gradually increase their time outside over the course of a week. This strengthens the stems and prevents the leaves from getting "sunburned."
Selecting the Perfect Spot
Begonias are famous for their love of shade, but "shade" can mean different things. For more ideas on shade-loving bulbs, see Summer Bulbs for Shady Gardens.
- Dappled Light: This is the gold standard for begonias. Think of the light under a leafy tree.
- Morning Sun: Begonias generally enjoy the cool light of the morning.
- Afternoon Protection: Avoid spots that get blasted by the hot, direct sun between 12:00 PM and 4:00 PM. This can scorch the leaves and cause the flowers to wilt.
Soil and Drainage
The right plant in the right place starts with the soil. Begonias need soil that is rich in organic matter but allows water to move through freely. If your garden soil is heavy clay, consider planting your begonias in raised beds or containers where you can control the drainage better. Adding a bit of compost or leaf mold can help create that fluffy, nutrient-rich environment they love.
Planting Outdoors: Depth and Spacing
Whether you are transplanting a started plant or putting a dormant tuber directly into the ground, getting the depth and spacing right is a quiet win for garden success.
Depth for Direct Planting
If you are planting dormant tubers directly outside in late spring:
- Dig a shallow hole about 1 to 2 inches deep.
- Place the tuber with the hollow side up.
- Cover with an inch of soil.
- Water gently to settle the earth.
Spacing for Airflow
Begonias like a bit of breathing room. Good air circulation helps prevent common issues like powdery mildew (a white, dusty fungus that can appear on leaves). For more spacing guidance, see How Far Apart Should Begonias Be Planted?.
- Upright Begonias: Space these about 10 to 12 inches apart.
- Cascading (Pendula) Begonias: These are usually planted in hanging baskets or the edges of pots. You can plant 2 or 3 tubers in a 12-inch hanging basket for a full, lush look.
What to do next:
- Wait until nighttime temperatures are consistently above 50–55°F before moving plants outside.
- Check the drainage of your chosen garden spot.
- Space plants according to their variety (upright vs. cascading).
- Add a thin layer of mulch to help keep roots cool and retain moisture.
Water and Fertilizer: The Essentials
Once your begonias are established in the garden or their final containers, their needs are fairly simple. They are consistent plants that reward regular care.
Watering Correctly, Not Constantly
The goal for begonia watering is "moist but not soggy." Because their stems and leaves are succulent (they hold a lot of water), they can handle a little bit of drying out better than they can handle sitting in a puddle.
- Containers: Pots and hanging baskets dry out faster than the ground. In the heat of summer, you might need to water daily.
- Garden Beds: Check the soil every few days. If the top inch is dry, give them a deep soak.
- Avoid the Foliage: Try to water at the base of the plant rather than splashing the leaves. Wet leaves in the evening can lead to fungal problems.
Feeding Your Begonias
Begonias are "heavy feeders," meaning they use a lot of energy to produce those massive, beautiful blooms all season long.
- Balanced Fertilizer: Use a balanced, water-soluble fertilizer (like a 10-10-10 or 20-20-20) every two weeks.
- Bloom Boosters: As the summer progresses, you can switch to a fertilizer with a higher middle number (phosphorus) to encourage even more flowers.
- Always Dilute: It is better to use a weaker strength more often than to hit the plants with a concentrated dose that might burn the tender roots.
Key Takeaway: Consistent moisture and a regular feeding schedule every two weeks are the secrets to a begonia display that lasts until the first frost.
Choosing the Right Begonia Variety
Not all begonias are the same, and picking the right type for your specific spot makes gardening much easier. For a broader overview, see All About Begonias.
Upright Begonias
These are the classic Upright Double Begonias. They grow on sturdy stems and produce large, often double flowers that look like roses or camellias. They are perfect for the front of a shady border or as the centerpiece of a patio planter.
- Roseform Pink: Huge, symmetrical blooms.
- Fimbriata: These have ruffled, fringed edges that add a unique texture to the garden.
- Picotee White: These flowers have a different color on the edge of the petal than in the center, creating a beautiful "halo" effect.
Cascading Begonias (Pendula)
If you have hanging baskets or window boxes, Hanging Begonias are the way to go. Instead of growing straight up, their stems gracefully arch over the sides of the container, covered in a curtain of blooms. They are particularly effective in areas where they can be viewed at eye level.
Fragrant Varieties
While many begonias are grown just for their looks, some varieties, like Odorata White, offer a light, sweet scent. These are wonderful for porch containers where you can enjoy the fragrance on a warm summer evening.
Maintaining Your Begonias All Season
To keep your begonias looking like they belong on a magazine cover, a little bit of "grooming" goes a long way.
Deadheading for More Blooms
Deadheading is simply removing the flowers once they start to fade. When a flower begins to wilt or turn brown, snip it off about an inch below the bloom. This prevents the plant from putting energy into making seeds and instead tells it to keep producing new flower buds. It also keeps the plant looking tidy.
Managing Pests and Weather
Begonias are generally quite hardy when it comes to pests, but they can occasionally attract slugs or snails in very damp environments. Keeping the area around the plants clean of fallen leaves can help.
If a summer storm brings heavy wind or rain, upright begonias with very large flowers might need a little support. A simple bamboo stake and a loose tie can keep a top-heavy stem from snapping.
Pinching Back
For cascading varieties, some gardeners choose to "pinch back" the growing tips when the stems are about 6 inches long. This encourages the plant to branch out and become bushier, resulting in even more flowers. It might delay the first blooms by a week or two, but the end result is a much fuller plant.
Preparing for the End of the Season
As the days get shorter and the first frost approaches, your begonias will start to slow down. Since these are tropical plants, they won't survive a cold winter in the ground in most of the US.
Lifting and Storing Tubers
One of the best things about tuberous begonias is that you can save the tubers and plant them again next year!
- Stop Fertilizing: In late summer, stop feeding the plants to let them naturally prepare for dormancy.
- Wait for Frost (or Yellowing): You can wait until the first light frost turns the leaves black, or simply wait until the foliage starts to turn yellow.
- Dig Gently: Carefully lift the tubers out of the soil.
- Dry Them Out: Cut the stems back to about an inch and let the tubers dry in a cool, dry place for a few days.
- Storage: Once dry, brush off the excess soil and store them in a box of peat moss or sawdust in a cool (40–50°F), dark place like a basement or garage.
Common Myths and Realistic Expectations
Gardening should be a source of joy, not stress. While begonias are relatively easy, it helps to have realistic expectations about how they grow.
"They won't grow in the sun"
While begonias are shade-lovers, they don't want to live in a dark cave. They need bright, indirect light to produce flowers. If your begonia has lots of leaves but no blooms, it might actually need a little bit more light.
"I need a greenhouse to start them"
You absolutely do not need a greenhouse. A simple tray on a kitchen counter or a shelf with a shop light is more than enough to get your tubers started in the spring.
"More water equals more flowers"
This is a common mistake. Overwatering is the most frequent cause of trouble with begonias. Always check the soil with your hand before adding more water. If the soil is still damp, wait a day.
One Change at a Time
If your plant isn't performing the way you want, try changing just one thing. Move it to a slightly brighter spot and wait a week. Or adjust your watering schedule and observe. Stacking multiple "fixes" at once makes it hard to tell what actually helped the plant.
Why Quality Matters
When you are starting with tubers, the quality of the "starting material" is the single biggest factor in your success. At Longfield Gardens, we work with experienced growers to ensure that the tubers we ship are the largest, healthiest sizes available. Larger tubers have more stored energy, which leads to bigger plants and more flowers in their very first season.
We stand behind the quality of everything we ship with a 100% quality guarantee. We want your tubers to arrive in prime condition and be true to the variety you ordered. If you ever have a concern about the performance of your plants during their first growing season, our customer service team is ready to help with replacements or advice.
Conclusion
Whether you decide to start your begonia tubers indoors today or wait a few more weeks for the garden soil to warm up, you are on your way to a stunning summer display. By following the simple rules of right plant, right place, and paying attention to the timing of your local frost dates, you can enjoy these tropical treasures regardless of your skill level.
Gardening is a journey of observation and small successes. There is nothing quite like the feeling of seeing those first rose-shaped blooms open up in a shady corner of your yard. We are here to support you with quality plants and practical advice every step of the way, and you can always Contact Us.
- Start indoors 8–12 weeks before the last frost for early color.
- Plant hollow-side up and barely cover with soil.
- Choose a spot with dappled shade and well-draining soil.
- Water consistently but avoid letting the tubers sit in soggy ground.
Gardening is meant to be a rewarding and relaxing hobby. Take it one step at a time, watch your begonias grow, and enjoy the vibrant beauty they bring to your home.
Ready to start your shade garden? Explore our collection of premium begonia tubers at Longfield Gardens and find the perfect colors for your space.
FAQ
Can I plant begonia tubers in the ground if it might still frost?
No, it is best to wait until all danger of frost has passed before planting begonia tubers directly in the ground. Begonias are tropical plants and their tender sprouts can be easily damaged or killed by freezing temperatures. If you want to start them while it is still cold, plant them in containers indoors and move them outside once the weather is consistently warm.
How deep should I plant my begonia tubers?
Begonia tubers should be planted quite shallowly. Place the tuber in the soil with the hollow (concave) side facing up and cover it with only about 1/2 inch to 1 inch of potting mix or garden soil. Planting them too deep can make it difficult for the young sprouts to reach the surface and may increase the risk of the tuber rotting.
Which side of the begonia tuber faces up when planting?
The hollow or indented side of the begonia tuber should always face upward. This indented "bowl" is where the growth points, or eyes, are located. The rounded, smooth side should face downward into the soil, as this is where the root system will develop.
Do I need to water my begonia tubers every day?
You should only water your begonias when the top inch of soil feels dry to the touch. While begonias enjoy consistent moisture, they are very susceptible to rot if the soil remains soggy or waterlogged. For indoor starts, water sparingly until you see active growth; for outdoor plants, check the soil every few days and adjust based on your local rainfall and temperature.