Introduction
Shade gardens often feel like a quiet retreat, and adding the lush, vibrant colors of begonias is one of the most rewarding ways to brighten those cooler corners. These versatile plants offer a spectacular range of shapes and colors. They transform hanging baskets, patio pots, and garden borders into tropical-looking displays that last all summer. At Longfield Gardens, we want to help you make the most of your gardening season by ensuring your plants get off to a strong start.
Knowing when is a good time to plant begonias is the first step toward a garden full of rose-like blooms and striking foliage. This guide is for anyone looking to add reliable color to their landscape, whether you are a beginner or a seasoned gardener. We will cover everything from starting your tubers indoors to the perfect moment for moving them into the sunshine. Getting the timing right ensures your plants stay healthy and bloom continuously until the first autumn frost.
Understanding the Best Time to Plant Begonias
Begonias are tropical plants by nature. They love warmth and humidity, and they have very little tolerance for the cold. Because of this, the most important rule for timing is to wait until the threat of frost has completely passed. In most parts of the United States, this means mid-to-late spring.
The exact date depends heavily on your local weather and your USDA hardiness zone. If you plant too early in cold, wet soil, the tubers or roots may struggle to grow. Instead, we recommend waiting until the ground feels warm to the touch. When the soil reaches about 60°F, begonias feel right at home and will begin to sprout with enthusiasm.
If you are eager to see flowers earlier in the summer, you do not have to wait for the outdoor weather to cooperate. You can give your begonias a head start by starting them indoors. This simple step can result in a much longer blooming season. It allows you to enjoy the first flowers weeks before those planted directly in the ground would even begin to bud.
Starting Tuberous Begonias Indoors
Upright tuberous begonias are the stars of the shade garden. They produce large, dramatic flowers that often look like roses or camellias. Because they take a little while to wake up from their winter dormancy, starting them indoors is a great way to jump-start the season.
When to Start Indoors
A good time to start your begonia tubers indoors is about 8 to 12 weeks before your area's last expected frost date. If you want a step-by-step walkthrough, see our How to Start Tuberous Begonias Indoors guide. For many gardeners in the northern states, this usually falls in late February or March. This window gives the tubers enough time to develop a strong root system and a few inches of leafy growth before they move outside.
Preparing Your Indoor Space
You do not need a greenhouse to be successful. A warm room with a bright window or a simple grow light works perfectly. The goal is to provide a consistent temperature between 60°F and 70°F. If the room is too cold, the tubers will stay dormant. If it is too hot and dark, the stems might become thin and weak as they reach for light.
The Planting Process
When you receive your tubers from us, they will look like firm, brown discs. Look closely at the tuber to find the "indented" or hollow side. This is the top where the sprouts will emerge. The rounded side is the bottom where the roots will grow.
Fill a shallow tray or small individual pots with a light, moistened potting mix. Place the tubers on the surface of the soil with the hollow side facing up. You only need to cover them with about half an inch of soil. Some gardeners prefer to leave the very top of the tuber exposed until they see the first green nubbins appear.
Key Takeaway: Starting begonia tubers indoors 2-3 months before the last frost date gives you larger plants and earlier blooms once summer arrives.
When to Move Begonias Outdoors
Transitioning your plants from the comfort of your home to the garden requires a bit of patience. Even if the days feel warm, the nights can still be quite chilly. Begonias are sensitive to temperature swings, so it is best to be cautious.
Checking Nighttime Temperatures
The most reliable indicator that it is a good time to plant begonias outside is the nighttime temperature. Wait until the nights are consistently 50°F or warmer. If there is even a small chance of a late-season frost, keep your plants indoors or under a covered porch for a few more days.
Hardening Off Your Plants
If you started your begonias indoors, they need to get used to the outdoor environment. This process is called "hardening off." Think of it as a slow introduction to the real world. Start by placing your pots in a shaded, protected spot outside for just a couple of hours during the warmest part of the day.
Each day, increase the amount of time they spend outside. After a week or ten days of this gradual exposure, your begonias will be strong enough to stay out all night. This prevents "transplant shock," which can cause leaves to drop or growth to stall.
Soil Readiness
The soil in your garden beds takes longer to warm up than the air. If you are planting directly into the ground rather than in pots, wait until the soil is around 60°F. If you plant into cold, soggy mud, the tubers may rot before they have a chance to grow. A simple way to check is to see if other spring plants, like lilacs, have finished blooming and are fully leafed out.
Timing for Different Types of Begonias
While tuberous begonias are very popular, there are other varieties that home gardeners love. Each has a slightly different preference for timing and environment.
Wax Begonias (Fibrous-Rooted)
Wax begonias are the hardy workers of the garden. They have waxy leaves and clusters of small flowers. They are often sold as small "starts" or "plugs" in garden centers. Because they have fibrous roots rather than a large tuber, they establish themselves quickly. A good time to plant wax begonias is immediately after the last frost. They are slightly more tolerant of sun than tuberous types, but they still appreciate a break from the intense afternoon heat.
Rex Begonias (Rhizomatous)
Rex begonias are grown primarily for their incredible foliage. Their leaves feature swirls of silver, purple, pink, and green. These are even more sensitive to cold than other types. Most gardeners treat these as houseplants or move them outside only during the height of summer. Wait until the weather is truly warm and humid before placing Rex begonias on a shaded patio.
Angel Wing and Cane Begonias
Angel Wing and Cane Begonias grow tall on stems that look like bamboo. They are wonderful for large containers. Like their cousins, they require warm temperatures above 50°F at night. They are excellent choices for areas with long, hot summers because they can handle a bit more humidity and heat than the large-flowered tuberous types.
Choosing the Right Planting Location
Once you have the timing right, the next step is finding the perfect home for your begonias. The right location will help your plants thrive and bloom without stress.
Light Requirements
Most begonias prefer filtered light or dappled shade. Imagine the light under a tall tree or on a porch that gets morning sun but is shaded by 1:00 PM. Direct, midday sun can be too intense and may scorch the leaves. If you notice the edges of the leaves turning brown and crispy, the plant is likely getting too much sun.
Soil and Drainage
Begonias need soil that stays moist but never soggy. They are prone to rot if they sit in standing water. If you are planting in the ground, ensure the area has good drainage. You can improve heavy clay soil by mixing in some compost or leaf mold. This creates a "fluffier" texture that allows roots to breathe.
For container gardening, the Assorted Bold Container for Shade Collection is a ready-made option. A high-quality potting mix designed for flowers is usually best. These mixes are lightweight and hold just enough moisture to keep the plant happy without drowning the roots.
What to Do Next: A Quick Checklist
- Check your local last-frost date.
- Order your tubers from us about 8-12 weeks before that date.
- Find a warm, bright indoor spot for starting the tubers.
- Gather shallow pots and a light potting mix.
- Prepare your outdoor pots or garden beds with fresh compost.
Steps for Planting Begonia Tubers Outdoors
When the weather is finally warm enough, follow these simple steps to get your begonias in the ground or in their final outdoor pots.
Step 1: Prepare the Soil
Loosen the soil to a depth of about 6 inches. If you are planting in a container, fill it with fresh potting soil, leaving about two inches of space at the top.
Step 2: Placement and Depth
If you are planting begonia tubers that were not started indoors, place them 8 to 12 inches apart. Dig a shallow hole and set the tuber inside with the hollow side facing up. Cover it with about one inch of soil. If you are transplanting begonias that already have leaves, dig a hole just deep enough to accommodate the root ball. The top of the root ball should be level with the surrounding soil surface.
Step 3: Settling the Plants
Gently press the soil around the plant to remove any large air pockets. Water the area lightly. For tuberous begonias, it is important not to overwater at this stage. You want the soil to be damp like a wrung-out sponge, but not dripping wet.
Step 4: Add a Layer of Mulch
In garden beds, a thin layer of organic mulch can help keep the soil temperature consistent and retain moisture. This is especially helpful if you live in a region where the sun can dry out the soil quickly.
Key Takeaway: Proper spacing and shallow planting are the "quiet winners" of begonia gardening. Giving them room to breathe prevents disease and encourages more flowers.
Caring for Your Begonias After Planting
After the initial planting, begonias are relatively low-maintenance, but a little bit of consistent care goes a long way.
Watering Rules
The best way to water begonias is to focus on the soil rather than the leaves. Keeping the foliage dry helps prevent mildew and fungal issues. Water deeply, then allow the top inch of soil to dry out before watering again. If the stems feel soft or mushy, that is a sign the plant is getting too much water.
Fertilizing for Success
Begonias are "heavy feeders," meaning they need plenty of nutrients to keep producing those big blooms. Start using a balanced, water-soluble fertilizer about a month after planting. Applying it at half-strength every two weeks is a great way to provide a steady supply of energy. Once you see flower buds forming, you can switch to a fertilizer with a higher phosphorus count to encourage even more blossoms.
Deadheading
Most modern begonia varieties are "self-cleaning," which means the old flowers fall off on their own. However, if you see spent blooms hanging onto the plant, you can gently pinch them off. If you like nonstop blooms, the Non Stop Begonias collection is a great fit. This keeps the plant looking tidy and encourages it to put its energy into new growth rather than seed production.
Realistic Expectations for Your Garden
Every garden is a unique environment. While we provide general timelines, your specific microclimate—the amount of wind, the exact shade levels, and your local soil—will influence how fast your begonias grow. Some years, a cool spring might mean your plants grow a bit slower at the start. Do not worry; once the summer heat arrives, they usually catch up quickly.
If you live in a very hot climate, your begonias might take a "break" from blooming during the hottest weeks of July. This is normal. Continue to water them and keep them in the shade, and they will start blooming again as soon as the temperatures dip slightly.
Many garden plants can be toxic if eaten by curious pets or small children. It is always a good idea to keep your begonias in a place where they can be admired safely. Hanging baskets are a wonderful way to keep beautiful blooms out of reach of pets while still enjoying the color at eye level.
Storing Tubers for Next Year
One of the best things about tuberous begonias is that they can last for many years. Because they are not winter-hardy in most of the U.S., you will need to bring them inside for the winter if you want to keep them.
When the leaves begin to turn yellow in late autumn, or after the first very light frost, stop watering the plants. Let the foliage die back naturally. This allows the plant to send all its remaining energy back into the tuber for next year.
Dig the tubers out of the ground or remove them from their pots. Shake off the excess soil and let them dry in a cool, airy spot for a few days. Once they are dry, you can store them in a box filled with peat moss or sawdust. Keep the box in a cool, dark, and dry place (like a basement or closet) where temperatures stay around 50°F. Next spring, you can start the whole exciting cycle over again!
Conclusion
Finding the right time to plant begonias is a simple way to ensure your garden is successful and stress-free. By waiting for warm soil and protecting these tropical beauties from the frost, you set the stage for a summer filled with color. Whether you choose to start your tubers indoors for an early show or wait for the natural warmth of late spring, the reward is a lush, beautiful landscape.
At Longfield Gardens, we take pride in providing high-quality tubers that are ready to perform in your yard. If you are planning an order, review our shipping information for timing details. We stand behind our plants with a quality guarantee because we want your gardening experience to be as rewarding as possible.
- Wait for nighttime temperatures to stay above 50°F before moving plants outside.
- Start tubers indoors 8-12 weeks early for a head start on blooms.
- Always prioritize well-draining soil and filtered light.
- Store your tubers in a cool, dry place over winter to enjoy them again next year.
Key Takeaway: Gardening is a journey that rewards patience. By following the natural cues of the weather and soil, you can grow begonias that look like they belong in a professional botanical garden.
FAQ
Can I plant begonias in full sun?
Most begonias prefer partial shade or filtered light, especially in warmer climates where the afternoon sun is intense. However, some wax begonias with darker or bronze-colored leaves are more tolerant of sunny spots. If you plant in a sunny area, be sure to monitor the soil moisture closely, as it will dry out much faster.
How deep should I plant begonia tubers?
Begonia tubers should be planted quite shallowly. Indoors, they can be placed on the surface or covered with just a tiny bit of soil. Outdoors, cover them with no more than one inch of soil. Planting them too deep can prevent the sprouts from reaching the surface and may cause the tuber to rot.
What should I do if a late frost is predicted after I plant?
If you have already moved your begonias outdoors and a surprise frost is in the forecast, you must protect them. For plants in containers, the easiest solution is to move them into a garage or shed overnight. For plants in the ground, cover them with a frost blanket, an old sheet, or even a large plastic bucket to trap the heat from the soil.
Why are my begonia tubers not sprouting?
Begonia tubers can be slow to wake up, sometimes taking 2 to 4 weeks to show signs of life. They require consistent warmth to begin growing. If your indoor space is below 60°F, they may stay dormant longer. Ensure the soil is damp but not soaked, as too much water before the plant has leaves can cause the tuber to fail.
