Introduction
Begonias are a garden favorite for a reason. These versatile plants bring lush, tropical beauty to shady corners where many other flowers struggle to thrive. Whether you are looking for the massive, rose-like blooms of Upright Double Begonias or the colorful, waxy leaves of bedding varieties, there is something truly rewarding about seeing those first sprouts emerge. At Longfield Gardens, we believe that every gardener can enjoy success with begonias by following a few simple steps.
Getting the timing right is the most important part of growing begonias. Because they are native to warm, tropical climates, they are very sensitive to the cold. If you plant them too early, the cool soil can slow their growth or cause the tubers to rot. If you wait too long, you might miss out on weeks of beautiful summer color. This guide is designed for home gardeners who want to know exactly when to get their begonias in the ground or in containers for the best possible results.
We will cover everything from starting your tubers indoors to the perfect outdoor temperatures for transplanting. You will learn how to read your local weather patterns and use simple cues from nature to decide when to plant. By the end of this article, you will have a clear timeline for your garden, ensuring your begonias grow strong and bloom beautifully all season long.
Timing your planting correctly ensures that your begonias have the warmth and light they need to flourish from the very first day.
Understanding the Role of Temperature
The most important rule for planting begonias is to wait for the warmth. Most begonias are tropical or semi-tropical perennials. In most parts of the United States, we grow them as annuals because they cannot survive a frost. Because of their tropical heritage, their internal clock is tied closely to temperature rather than just the calendar date.
Soil Temperature vs. Air Temperature
It is easy to get excited on the first warm day of spring and head out to the garden. However, air temperature and soil temperature are two different things. Soil takes much longer to warm up than the air does. While the sun might feel warm on your skin in April, the ground could still be chilly from the winter months.
For begonias, the ideal soil temperature is at least 60°F. If the soil is colder than this, the tubers or roots will sit dormant. In wet spring weather, dormant tubers in cold soil are at a higher risk of rot. A simple way to check is to use a soil thermometer or wait until you see other warm-weather plants, like tomatoes or peppers, being planted in your neighborhood.
Nighttime Lows Matter Most
Even if your days are sunny and 70°F, the nighttime temperatures are the real deciding factor. Begonias prefer nights that are consistently above 50°F. If your local forecast still shows "dips" into the 30s or 40s, it is best to keep your plants protected. Cold nights can stunt the growth of the plant, leading to fewer flowers later in the summer.
Key Takeaway: Begonias thrive when the soil is 60°F and nighttime air temperatures stay above 50°F. Patience in the spring leads to much faster growth once the heat of summer arrives.
Starting Tuberous Begonias Indoors
One of the best ways to get a head start on the season is to follow our How to Plant and Care for Begonias guide. This is particularly helpful if you live in a northern climate with a short growing season. By starting them inside, you can enjoy flowers several weeks earlier than if you waited to plant them directly in the garden.
The Ideal Window
The best time to start begonia tubers indoors is about 8 to 12 weeks before the average last frost date in your area. For many gardeners, this means starting in late February or March. This window gives the tuber enough time to wake up, develop a strong root system, and produce its first set of leaves before it moves outside.
How to Tell When They Are Ready
When you receive your tubers from us, they may look like small, brown, shriveled discs. This is perfectly normal. They are simply dormant. To start them, place them in a shallow tray of moist potting soil. One side of the tuber is usually indented or hollow—this side should face up.
Within a few weeks of being in a warm room (around 70°F), you will see small pink or red buds beginning to sprout from the hollow center. This is the sign that your timing was perfect. Once these sprouts are about an inch tall, you can move the tubers into individual pots with more soil.
What to Do Next: Starting Indoors
- Check your local estimated last frost date.
- Count back 8 to 12 weeks to find your start date.
- Place tubers in a warm, bright room (but not in direct, hot sun).
- Keep the soil lightly moist, like a wrung-out sponge, but never soggy.
Timing by Begonia Type
Not all begonias are exactly the same. While the general rules for warmth apply to all of them, the specific timing can vary slightly depending on the variety you are growing.
Tuberous Begonias
These are the stars of the shade garden, known for their large, rose-like flowers like Begonia Upright Double Roseform Pink. Because they grow from a thick, fleshy tuber, they carry their own energy reserve. This means they can be started indoors very early. If you miss the 8-week window, don’t worry. You can still plant them later, but they will simply start blooming later in the summer.
Wax Begonias (Fibrous-Rooted)
Wax begonias are often sold in "flats" or small "six-packs" at garden centers. These are typically grown from seed, which can take a very long time. Most home gardeners buy these as established small plants. The best time to plant these is strictly after all danger of frost has passed. They do not have the energy reserve of a tuber, so they are more susceptible to being set back by a late-season chill.
Rex and Cane Begonias
Rex begonias are grown for their spectacular foliage, while Cane begonias (like the popular Angel Wing) are known for their upright growth. These are often kept as houseplants year-round. If you want to move them outside for the summer to decorate your porch or patio with Hanging Begonias, the timing should be even more conservative. Wait until the weather feels truly like summer—usually late May or early June in many zones—before moving these "residents" outside.
Using USDA Hardiness Zones as a Guide
At Longfield Gardens, we use USDA hardiness zones to help determine when it is safe to ship and plant. Begonias are generally hardy in zones 9 through 11. In these warm regions, they can often stay in the ground year-round. For everyone else in zones 3 through 8, begonias are treated as summer guests.
Shipping and Arrival
We time our shipments based on your hardiness zone. This ensures that your tubers arrive at the right time for planting in your specific climate. Shipping Information explains how your order is scheduled. If you aren't ready to plant them as soon as they arrive, simply keep them in a cool, dry, dark place until you are ready to start them in trays.
Regional Variations
- Southern Climates: In places like Florida or Texas, the "best time" to plant might be much earlier, such as February or March. In these areas, the challenge is often the intense summer heat rather than the spring cold.
- Northern Climates: In places like Maine or Minnesota, you may need to wait until June to move plants outside. Starting indoors is almost a necessity in these regions to ensure a long bloom period.
"Gardening success is less about following a strict date on a calendar and more about observing the rhythm of your local climate."
Transitioning to the Outdoor Garden
Once the weather has warmed up and your begonias are growing well in their pots, it is time to move them to their permanent summer home. However, you cannot move them from a cozy indoor environment to the great outdoors all at once. This transition requires a process called "hardening off."
The Hardening Off Timeline
The best time to start this process is about a week after your last frost date, provided the 10-day forecast looks clear. Hardening off takes about 7 to 10 days.
- Days 1-3: Place your begonias outside in a protected, fully shaded spot for 2 to 3 hours in the afternoon. Bring them back inside before the temperature drops in the evening.
- Days 4-6: Increase their outdoor time to 5 or 6 hours. Move them into a spot that gets a tiny bit of dappled light, but keep them away from direct, harsh sun and wind.
- Days 7-10: If the nights are staying above 50°F, you can leave them out overnight in a protected area.
- Final Step: After 10 days, they are ready to be planted in the ground or their final decorative containers.
Choosing the Right Planting Day
Even if the calendar says it is time, try to pick a day that is overcast or slightly cloudy for the actual transplanting. Moving a plant into the ground on a hot, scorching, sunny day can cause "transplant shock." A calm, cloudy day allows the plant to settle into its new home without the stress of intense sunlight.
Factors That Can Change Your Timeline
While we provide general windows for planting, nature sometimes has its own plans. Being flexible is part of the fun of gardening. Here are a few things that might shift your "best time" by a week or two.
Heavy Spring Rains
If your area is experiencing an unusually wet spring, it is better to wait to plant your begonias in the ground. Even if it is warm enough, soil that is completely saturated with water can suffocate the roots or cause tubers to rot. If the ground feels like a sponge when you step on it, give it a few days to dry out. Begonias in containers are safer during rainy periods because pots usually drain much faster than garden beds. If you prefer a container-ready option, Begonia Hanging Pink Balcony is a good fit for a shady porch or deck.
Microclimates in Your Yard
You might find that some parts of your yard are ready for planting sooner than others.
- Near the House: Soil near the foundation of a heated home often stays a few degrees warmer than the rest of the garden.
- Patios and Stone: Stone and concrete soak up heat during the day and radiate it at night. This can make a patio a great spot for early container planting.
- Low Spots: Cold air settles in low-lying areas of a yard. If your garden is at the bottom of a hill, you might need to wait a few extra days to avoid a "late frost pocket."
Potting vs. Ground Planting
If you are planting in containers, you can often start a bit earlier, and How Many Begonia Plants Per Pot? can help you plan the spacing. If a surprise cold snap is predicted, you can simply tuck your pots into the garage or mudroom for the night. Ground planting is more permanent, so it requires more certainty about the weather.
Visual Cues from Nature
If you don't like checking weather apps or soil thermometers, you can use "phenology"—the study of natural cycles. Many gardeners find that watching other plants is the most reliable way to know when to plant begonias.
The "When to Plant" Checklist
- Wait for the Lilacs: Many experienced gardeners wait until common lilacs have finished blooming before they put tender annuals like begonias in the ground.
- Oak Leaves: A classic rule of thumb is to wait until oak leaves are the size of a squirrel's ear. This usually signals that the soil has reached a safe temperature.
- The Grass Factor: When your lawn starts needing a weekly mow, the soil is active and warm enough for most garden plants.
Using these cues helps you stay in tune with your specific microclimate, which is often more accurate than a general zone map.
Planting for a Long Season of Color
The goal of timing your planting correctly is to maximize the time your begonias spend in bloom. Begonias are unique because they don't usually have a "peak" and then fade; they keep producing new flowers until the first frost of autumn.
Extending the Season
By starting your tubers in March, moving them outside in May, and keeping them well-watered through the summer, you can enjoy up to five or six months of color with Begonia Non Stop Mix. If you plant them too late—say, in late June—you might only get two months of flowers before the cold returns.
Late Season Timing
As summer turns to fall, your timing focus shifts to the first frost. While begonias love the warmth of late summer, they will stop blooming as soon as the first hard frost hits. If you want to save your tuberous begonias for next year, the best time to dig them up is right after the first light frost has blackened the foliage; our FAQs - Spring-Planted Bulbs cover storage and other timing questions.
What to do next: Success Steps
- Check your nighttime temperatures for a 10-day streak above 50°F.
- Check your soil moisture; ensure it is not waterlogged.
- Prepare your pots or garden beds with a well-draining potting mix.
- Begin the hardening off process if your plants have been indoors.
Common Timing Questions
Many gardeners worry that they have "missed the boat" if they didn't start their tubers in the winter. The truth is, gardening is very forgiving. Even if you plant your begonias a little late, they will still grow. They are vigorous plants that want to succeed.
If you find yourself with tubers in May that haven't been started yet, you can plant them directly into the ground or pots. They will skip the "indoor head start," but the warm soil of late spring will encourage them to sprout quickly. For a broader overview of begonias, see All About Begonias. You might see flowers in August instead of July, but the beauty will still be there.
The only real "mistake" is planting too early into cold, wet soil. It is always better to wait one week too long than to plant one week too early. A begonia planted in warm soil will quickly outgrow one that has been sitting stunted in cold soil.
Summary of the Begonia Planting Timeline
To keep things simple, here is a quick reference for your planting schedule:
- Late Winter (Feb/March): Start tuberous begonias indoors in trays.
- Early Spring (April): Watch for sprouts and move to individual pots.
- Mid-Spring (Post-Frost): Begin hardening off plants for outdoor life.
- Late Spring (May/June): Transplant to garden beds or permanent containers.
- Summer: Enjoy continuous blooms and keep the soil evenly moist.
- Autumn: Dig up tubers for storage after the first light frost.
By following this rhythm, you ensure that your plants are always in the right environment for their current stage of growth. This leads to bigger leaves, stronger stems, and more abundant flowers.
FAQ
Can I plant begonias before the last frost?
It is not recommended to plant begonias outdoors before the last frost, as they are very sensitive to freezing temperatures. Even a light frost can kill the foliage and damage the stems. If you want to start early, always do so indoors or in a greenhouse where you can control the temperature.
What is the ideal soil temperature for begonias?
Begonias prefer a soil temperature of at least 60°F. In colder soil, the plant’s metabolism slows down, and the roots or tubers are more likely to rot if the soil is wet. Using a soil thermometer or waiting until nights are consistently warm is the best way to ensure the soil is ready.
Is it too late to plant begonias in June?
No, it is not too late! While you will have a shorter blooming season than if you started them in March, begonias planted in June will grow very rapidly because the soil and air are already warm. They will continue to bloom until the first frost in autumn, often providing several months of beautiful color.
Do different types of begonias need to be planted at different times?
While all begonias need warmth, tuberous begonias are best started indoors 8-12 weeks before the frost to get a head start. Wax begonias and other bedding types are usually planted directly outside once the frost risk is gone. Foliage begonias, like Rex varieties, should wait for the most stable, warm summer weather before being moved outdoors.
Conclusion
Finding the best time to plant begonias is one of the simplest ways to ensure your garden is a success. By respecting their tropical nature and waiting for the soil and air to warm up, you give these plants the foundation they need to thrive. Whether you are starting them early in a sunny window or waiting for the lilacs to bloom before planting outside, the reward is a summer filled with vibrant, effortless color.
- Start tubers indoors 8-12 weeks before the last frost for the earliest flowers.
- Wait for nighttime temperatures to stay above 50°F before moving plants outside.
- Always "harden off" indoor plants for a week to get them used to the elements.
- Ensure your soil is well-drained and warm to prevent tuber rot.
At Longfield Gardens, we are here to help you every step of the way with our 100% Quality Guarantee. Gardening should be a joy, and with the right timing, your begonias will be a source of beauty and pride all season long.
"A little patience in the spring pays off with a spectacular display of color that lasts until the first frost of autumn."
Ready to start your shade garden? Visit our website to browse our selection and find the perfect begonias for your home.
