Introduction
There is a unique kind of joy in finding a plant that performs beautifully from the moment it hits the soil until the first frost of autumn. Wax begonias are exactly that kind of garden reliable. With their glossy, succulent-like leaves and a constant parade of cheerful blooms, these plants are a favorite for everything from formal garden borders to casual patio containers. Whether you are looking for a pop of bright red, soft pink, or pure white, these versatile annuals deliver nonstop color with very little fuss.
At Longfield Gardens, we want to help you make the most of every growing season. Achieving that "carpet of color" look depends heavily on one specific factor: timing. Because wax begonias are tropical in origin, they have a very specific set of preferences when it comes to temperature and light. They aren't just sensitive to frost; they truly thrive only when the soil and air have reached a consistent, cozy warmth. If you want to browse more options, our Begonia Flower Bulbs for Sale collection is a great place to start.
In this guide, we will explore exactly when to plant wax begonias to ensure they transition smoothly into your garden. We will cover regional timing, how to start them from seed indoors, and how to tell when your local environment is officially "begonia-ready." This article is for any gardener who wants to trade the guesswork for a clear, successful planting schedule.
Success with wax begonias starts with patience and a basic understanding of your local climate. By waiting for the right window of time, you allow these vigorous plants to establish strong roots and provide the lush, mounded display they are famous for.
Why Timing is Everything for Wax Begonias
Wax begonias (Begonia semperflorens) are technically tender perennials, but in most of the United States, we grow them as annuals. Because they originated in warm, humid climates in South America, their biological internal clock is set to "tropical." They do not have a dormant phase like a tulip or a daffodil. Instead, they are always "on," growing and blooming as long as the conditions allow.
This constant growth is why timing is so critical. If you plant them while the ground is still chilly, the plant won't just grow slowly—it may stop growing altogether. Cold soil can cause the roots to languish, making the plant more susceptible to issues before it even has a chance to bloom. Waiting for the right temperature isn't just about avoiding a freeze; it’s about giving the plant the energy it needs to fuel its "always flowering" nature. For a closer look at exposure, see our Where to Plant Wax Begonias for Best Growth and Blooms guide.
The 50-Degree Rule
The most important number to remember for wax begonias is 50°F (10°C). This is the minimum nighttime temperature these plants can comfortably handle. While a single night at 48°F might not be the end of the world, a string of cold nights will cause the foliage to turn a dull, muddy color and stop flower production.
For the most vigorous growth, many experienced gardeners wait even longer—until nighttime temperatures are consistently 60°F or higher. At this stage, the soil has usually warmed up enough to encourage rapid root expansion. When the roots are happy and warm, the top of the plant will quickly follow with a flush of new leaves and buds.
Soil Temperature vs. Air Temperature
It is easy to get excited on the first warm, sunny day of April. However, air temperature and soil temperature move at different speeds. Soil is a dense insulator; it takes weeks of warm air and sunshine to pull the winter chill out of the ground.
If you aren't sure if your soil is ready, you can use a simple soil thermometer. You are looking for a steady reading of at least 60°F at a depth of about 4 inches. If you don’t have a thermometer, a good rule of thumb is to wait until you see other warm-weather plants, like tomatoes or peppers, being sold at local nurseries. If it's safe for a tomato, it’s generally safe for a wax begonia.
Regional Planting Windows
In a country as large as the United States, "spring" happens at very different times. Understanding your USDA Plant Hardiness Zone is a great way to narrow down your planting window. We ship our plants based on these zones to ensure they arrive when it is nearly time to plant, typically about two weeks before the ideal window opens in your area. Check our Hardiness Zone Map to find your climate zone.
Southern and Tropical Climates (Zones 9–11)
In the warmest parts of the country, such as Florida, Southern Texas, and coastal California, wax begonias can often be treated as short-lived perennials. In these areas, the "when" of planting is much more flexible.
- Spring Window: February or March. This allows the plants to establish before the intense heat of mid-summer arrives.
- Fall Window: In South Florida and similar tropical pockets, wax begonias are often planted in October or November to serve as "winter" color, as they enjoy the milder temperatures of the tropical dry season.
Central and Mid-Atlantic Climates (Zones 6–8)
For gardeners in the middle of the country, the weather can be a bit of a roller coaster. One week feels like summer, and the next brings a surprise frost.
- The Window: Mid-April to mid-May.
- The Strategy: It is best to keep an eye on the long-term forecast. If Mother’s Day is usually the "safe" frost-free date in your town, aim to plant your wax begonias then. This ensures that the soil has had enough time to lose its winter dampness and chill. For more regional timing, our Shipping Information page explains how Longfield schedules orders by zone.
Northern and High-Elevation Climates (Zones 3–5)
In the North, the growing season is shorter, so it is tempting to rush. However, the ground stays cold much longer here.
- The Window: Late May to early June.
- The Strategy: Patience is your best friend. A wax begonia planted in the first week of June will often outpace one planted in early May because it won't be set back by "cold feet." In these zones, wax begonias truly shine in containers, which warm up much faster than the ground.
Key Takeaway: Always prioritize the local 10-day forecast over a calendar date. If nighttime lows are still dipping into the 40s, wait a week. Your begonias will thank you with faster growth once they are finally in the ground.
Starting Wax Begonias from Seed
Many gardeners choose to buy started plants from us or a local nursery, but you can also grow wax begonias from seed. This is a rewarding project for the winter months, but it requires a significant "head start" because begonia seeds are notoriously slow to get moving. For a step-by-step refresher, see our How to Plant and Care for Begonias guide.
The 12-to-16 Week Timeline
If you want to have wax begonias ready to go into the garden by late May, you need to start your seeds as early as January or February. Because the seeds are tiny—almost like dust—they take a long time to develop into a plant large enough to handle the outdoor environment.
Steps for Indoor Sowing
- Use a Seed-Starting Mix: Choose a fine-textured, sterile mix. "Drainage" is the most important factor here—it refers to how quickly water moves through the soil. You want a mix that stays moist but never feels like a swamp.
- Do Not Cover the Seeds: Wax begonia seeds need light to germinate. Simply sprinkle them on top of the moist soil and press them down very gently with your fingertip.
- Provide Warmth and Light: A heat mat can help maintain a soil temperature of about 70–75°F, which is ideal for germination. Once they sprout, they need 14–16 hours of bright light from a grow light or a very sunny window.
- Be Patient: It can take 14 to 21 days just for the seeds to sprout, and several more weeks before you see the first "true" leaves.
What to do next
- Check your local frost-free date.
- Count back 12–14 weeks if you plan to start from seed.
- Prepare your indoor seed-starting area with a light source and a heat mat.
- Keep the soil consistently moist but never soggy.
Transitioning to the Great Outdoors
Whether you grew them yourself or bought them as starts, your wax begonias shouldn't go directly from a cozy indoor environment to the garden. They need a transition period called "hardening off." This process helps the plant toughen up its leaves to handle direct sun, wind, and temperature swings. If you are planting in containers, our How Do You Plant Begonias: A Simple Step-by-Step Guide covers the basics from soil prep to planting.
The Hardening Off Schedule
About 7 to 10 days before your planned planting date, start moving your plants outside for short periods.
- Days 1-3: Place them in a sheltered, shady spot for 2-3 hours in the afternoon, then bring them back inside.
- Days 4-6: Increase their time outside to 5-6 hours and move them into a spot with a little bit of dappled sunlight.
- Days 7-10: If the nights are staying above 50°F, you can leave them outside overnight in their pots.
By the end of this week, the plants will be "acclimated" (adjusted) to the outdoor air, and the shock of transplanting will be significantly reduced.
Choosing the Right Spot for Your Timing
When you are ready to plant, the location you choose can actually affect how the plant handles the timing of the season. Wax begonias are incredibly versatile, but their leaf color gives you a clue about where they will be happiest.
Green-Leafed Varieties
Plants with bright green leaves generally prefer a bit of protection. They thrive in partial shade or areas with filtered sunlight. If you are planting early in the season when the sun is still relatively mild, they do fine. However, in the heat of July, they may scorch if they are in a spot with intense afternoon sun.
Bronze-Leafed Varieties
Varieties with dark, bronze-colored foliage, such as some of the "Surefire" or "Double Up" series we often carry, are the sun-lovers of the begonia world. The darker pigment in their leaves acts a bit like a built-in sunscreen. If your garden gets a lot of direct light, these are the best choice. They can handle the heat of a mid-June planting much better than their green-leafed cousins. For a fuller display, the How Far Apart Do You Plant Wax Begonias? Expert Spacing Tips guide is a helpful next step.
Soil and Space
No matter when you plant, wax begonias need soil that drains well. They have fleshy, succulent stems that store water, which makes them somewhat drought-tolerant, but it also makes them prone to "wet feet" if the soil is too heavy.
- In the ground: Mix in some compost or leaf mold to lighten up the soil.
- In containers: Use a high-quality potting mix.
- Spacing: Space them about 8 to 12 inches apart. While they look small at first, they will quickly mound out to fill the gaps as the weather warms up.
Care After Planting
Once your wax begonias are in the ground at the right time, they are remarkably low-maintenance. They are "self-cleaning," which means they drop their old blooms naturally, so you don’t have to spend your weekends deadheading (removing old flowers).
Watering Wisely
The best way to water wax begonias is to give them a deep soak and then let the top inch of soil dry out before watering again. Because their leaves are waxy, they are good at holding onto moisture. If you water them every single day regardless of the weather, you run the risk of root rot. In a standard summer, about an inch of water per week (from rain or your hose) is usually plenty.
Feeding for Flowers
To keep that nonstop bloom going, a little bit of fertilizer goes a long way. You can mix a slow-release fertilizer into the soil at planting time, or use a balanced, water-soluble fertilizer once a month. This provides the "fuel" the plant needs to keep producing new buds through the heat of August.
Dealing with "Leggy" Plants
If your begonias start to look a bit tall and thin by mid-summer—often called "leggy"—don't be afraid to give them a quick trim. Pinching back the tips of the stems encourages the plant to branch out, resulting in a fuller, more compact shape and even more flowers. For more care details, see our Growing Wax Begonias: A Simple Guide for Success article.
Overwintering: Extending the Season
As the end of the season approaches, you might find yourself wishing you could keep your wax begonias. The good news is that you can! Because they don't have a dormancy period, they make excellent houseplants.
Bringing Them Indoors
Before the first frost hits in the fall, you can dig up your favorite begonias and put them in pots, or simply bring your existing containers inside.
- Check for hitchhikers: Give the plants a gentle rinse with water to make sure no garden bugs are coming inside with them.
- Find a bright window: They love a sunny windowsill that gets bright, indirect light.
- Adjust your watering: Indoor air is often drier, but the plants grow more slowly in winter. Only water when the soil feels dry to the touch.
When the warm weather returns the following spring, you can move them back outside after the 50-degree nights return, giving you a massive head start on the next season. If you want to keep the plants going indoors, our How to Propagate Wax Begonias: A Simple Step-by-Step Guide is a useful next read.
Common Timing Questions
When we talk to gardeners, a few common questions about timing pop up every year. Getting these right can be the difference between a plant that struggles and one that flourishes.
"I planted too early and a frost is coming. What should I do?"
Don't panic! If you already have your begonias in the ground and a late-season frost is predicted, you can protect them. Cover the plants with an old bedsheet, a cardboard box, or a frost blanket. Avoid using plastic directly on the leaves, as it can transfer the cold. Remove the cover as soon as the sun comes up the next morning.
"Can I plant them in the middle of summer?"
Yes! While most people plant in the spring, wax begonias are very heat-tolerant. If you find a gap in your garden in July, you can certainly plant them then. Just be sure to water them more frequently for the first two weeks while their roots get established in the warm soil.
"Why aren't my begonias blooming yet?"
If your plants look healthy but aren't flowering, check your light and temperature. If the spring has been unusually cloudy and cool, the plants may just be waiting for more energy from the sun. Once the "dog days of summer" arrive with plenty of light and heat, they usually explode with color.
Conclusion
Wax begonias are a testament to the idea that some of the best things in the garden come to those who wait. By respecting their need for warm soil and frost-free nights, you set the stage for a spectacular display that lasts for months. Whether you choose the sun-loving bronze varieties or the shade-happy green ones, these plants offer a reliable, beautiful solution for almost any spot in your yard. For more ways to shop, explore our begonia collection.
At Longfield Gardens, we take pride in providing high-quality plants and the practical knowledge you need to help them thrive. We ship to the 48 contiguous United States, timing our deliveries so your plants arrive right when the planting window is about to open in your specific zone.
Gardening is a journey of observation and timing. This year, try waiting for that perfect 60-degree soil temperature before tucking your begonias into their new home. You will be rewarded with a lush, vibrant garden that remains the envy of the neighborhood all the way until autumn's first chill.
"The secret to successful gardening isn't a 'green thumb'—it's simply putting the right plant in the right place at the right time. For wax begonias, that means waiting for the warmth they love."
Summary Checklist for Success
- Wait for Warmth: Nighttime temperatures should be consistently 50°F, but 60°F is even better.
- Check the Soil: Ensure the ground is warm and drains well before planting.
- Match Leaf Color to Sun: Bronze leaves for sun, green leaves for shade.
- Harden Off: Give indoor plants a week to adjust to the wind and sun.
- Feed and Water: Provide a balanced fertilizer and deep, occasional watering.
FAQ
When is the best month to plant wax begonias outdoors?
For most of the United States, May is the ideal month. In southern regions (Zones 8-11), you can often plant in March or April. In northern regions (Zones 3-5), it is often best to wait until very late May or early June to ensure the soil is sufficiently warm. If you are still checking your timing, the Shipping Information page can help you match delivery to your zone.
Can wax begonias survive a light frost?
No, wax begonias are very sensitive to cold. A light frost will usually kill the foliage, and a hard freeze will kill the entire plant, including the roots. Always cover your plants if a surprise frost is predicted after you have planted them.
How early should I start wax begonia seeds indoors?
Because wax begonia seeds are tiny and grow slowly, you should start them 12 to 16 weeks before your last expected frost date. For many gardeners, this means sowing seeds in mid-January or early February to have garden-ready transplants by May.
Do wax begonias need full sun or shade?
They can handle both, depending on the variety. Bronze-leafed wax begonias are very heat and sun-tolerant and can thrive in full sun. Green-leafed varieties prefer partial shade or filtered light, especially in regions with very hot summer afternoons.
