Which Begonias Are Best for Pots and Window Boxes?
From the seed benches at Garden Starts Nursery, a real working nursery that grows plants from seed, we get one container question more than any other: which begonias are best for pots and window boxes? Here is the short answer. If you want blooms spilling over the edge, choose a trailing series like Illumination, Limitless, or Groovy. If you want the biggest flowers for a statement pot, choose an upright tuberous series like Nonstop or Prism. If the pot or box sits in sun, choose a compact, sun-tolerant series like On Top or Big. Every begonia we feature below is one we grow from seed ourselves, and each has a "Best for" note so you can match the plant to the container you own.
Begonias are some of the most reliable container flowers we grow from seed. They tolerate the warmth and wind of a porch, bloom steadily for months, and don't ask for much more than even moisture and a bright spot. The trick is matching the right series to the right container, because a series bred to cascade does nothing for a deep planter, and an upright tuberous type looks crowded in a shallow window box. This guide walks you through that choice.
What Makes a Begonia Good for a Pot or Window Box?
In our own seed-starting trays, the begonias that do best in containers share three traits:
- Growth habit: trailing begonias drape 10 to 18 inches over an edge, while compact upright types hold a tidy mound that fits small pots.
- Weather tolerance: window boxes dry out fast and take wind, so smaller foliage and sturdy stems hold up better.
- Bloom size: large-flowered tuberous begonias like Nonstop and Prism put on the most dramatic display in a big container, while smaller-flowered series fill space more evenly.
Which One Should I Choose?
Pick by the container and the look you want:
- Window boxes and hanging baskets: choose a trailing series like Illumination, Limitless, or Groovy.
- Large pots on a porch or patio: choose a big-bloomed upright type like Nonstop or Prism.
- Shallow boxes or full-sun spots: choose a compact, sun-tolerant series like On Top or Big.
- Medium planters that need a full, mounding plant: choose Go Go.
The Best Begonias for Pots and Window Boxes
These are the series and varieties we recommend most often to container gardeners. Each card tells you exactly what the variety is best for, so you can compare them at a glance.
Illumination Mix Best for: window boxes where you want a cascade of mixed blooms trailing well over the edge. This is the classic trailing begonia we reach for first. |
Limitless® Mix Best for: containers where you want trailing performance with larger flowers than a traditional cascade. Great in mixed window boxes. |
Nonstop Mix Best for: statement pots on porches and patios where you want the biggest begonia blooms. An upright tuberous series, not a trailer. |
Groovy Mix Best for: shallow window boxes and small hanging pots, where a compact trailing habit fills space without overwhelming it. |
On Top Sunset Shades Best for: window boxes and pots that sit in full sun. A compact, heat-tolerant series bred for container color. |
Go Go Rose Best for: medium and large planters where you want a full, mounding plant with oversized rose blooms. |
Prism Sunrise Best for: a bright bicolor statement in a single pot. Large tuberous blooms in warm sunrise tones. |
Big Begonia Rose Best for: low-maintenance mixed planters that see both sun and shade. Tough, tidy, and generous with its rose-pink blooms. |
Ready to plant? Browse the full Begonia Seeds collection to see every color and size we carry.
How to Start Begonias in Pots and Window Boxes from Seed
Begonia seeds are among the smallest we handle at the nursery, and pelleted seeds make them far easier to sow. From our seed benches, here is the process that works:
1. Start early, indoors
Sow begonia seeds 10 to 12 weeks before your last expected frost. Begonias are slow to reach transplant size, so the early start is what makes the season-long display possible.
2. Sow on the surface
Place one pelleted seed on the surface of moist seed-starting mix in each cell or small pot. Do not cover the pellet; begonia seeds need light to germinate.
3. Keep warm and evenly moist
Hold the tray around 70 to 75 degrees Fahrenheit with steady humidity. Germination typically takes 7 to 14 days, though cooler rooms slow it down.
4. Grow under bright light
Seedlings are tiny at first. A bright grow light keeps them from stretching while they develop their first true leaves.
5. Transplant into the container
Once seedlings have several sets of true leaves, move them into their final pots or window boxes. Fill a 10 to 12 inch window box with 3 to 5 trailing plants, and give each upright tuberous begonia a pot of its own, 8 to 10 inches wide or larger.
6. Harden off before moving outside
Introduce the plants to outdoor conditions gradually over a week. Then set the containers in the light level that suits the series: shade to part sun for the trailing types, and sun for On Top and Big.
Keeping Potted Begonias Happy
- Water evenly. Window boxes dry out quickly; check daily in summer heat and water when the surface begins to dry.
- Feed lightly through the season. A balanced liquid feed every few weeks supports steady blooming in containers.
- Deadhead spent blooms. Trimming faded flowers keeps the plants tidy and encourages more buds.
- Plan for cold weather. In mild climates begonias can carry over from year to year; elsewhere they are grown as annuals, and tuberous types can be lifted and stored. Our guide to whether begonias come back every year explains the types.
Frequently Asked Questions
Which begonias are best for window boxes?
Trailing series are the classic choice for window boxes because they cascade over the edge. Illumination, Limitless, and Groovy are the trailing series we recommend most, with Illumination the traditional favorite and Limitless offering larger flowers.
Can begonias grow in full sun in a pot?
Yes, if you choose a sun-tolerant series. On Top and Big are bred to handle sun in containers. In the hottest climates, a spot with afternoon shade reduces stress.
How many begonia seeds do I need per pot?
Sow one pelleted seed per cell or small pot, since germination is easier to manage that way. For the container itself, plan on 3 to 5 trailing plants for a 10 to 12 inch window box and one upright tuberous begonia per 8 to 10 inch pot.
When should I start begonia seeds indoors?
Start 10 to 12 weeks before your last expected frost date. Begonias are slow to reach transplanting size, and the early start is what supports a long summer display.
How long do begonias take to bloom from seed?
From sowing, begonias typically reach bloom a few months in, depending on the series, light, and temperatures. The exact timing varies, so starting early matters more than expecting a fixed date.
What size pot do begonias need?
Give upright tuberous begonias like Nonstop or Prism an 8 to 10 inch pot or larger, and trailing begonias a window box or hanging basket at least 10 to 12 inches wide. Bigger containers hold moisture longer, which begonias appreciate.
Are begonias perennials in pots?
It depends on your climate. In mild regions they can carry over from season to season; in cold-winter areas they are usually grown as annuals, and tuberous types can be lifted and stored. Our guide to begonia types covers the details.
Are begonia seeds hard to germinate?
They are small and need light, warmth, and steady moisture, but pelleted seeds remove most of the frustration. If seedlings stall, our article on why begonia seeds don't germinate walks through nine real fixes.
Explore More Begonia Guides
Where to Buy Begonia Seeds: Best Varieties for Shade, Hanging Baskets, Containers & Full Sun
Nonstop vs Illumination vs Limitless Begonias: Which Should You Grow?
Viking vs Hula vs Big Begonias: Which Seeds Should You Buy?
Do Begonias Come Back Every Year? Begonia Types Explained
Why Won't My Begonia Seeds Germinate? 9 Real Fixes
Shop Begonia Seeds
Trailing Begonia Seeds collection
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About Garden Starts Nursery
Garden Starts Nursery is a real working nursery that grows plants from seed. We start thousands of seedlings each season on our own benches, and everything we sell in our online seed catalog is a variety we know from hands-on experience. Begonias are among our favorite seed-started container plants, and we grow the trailing and tuberous series featured in this guide every year.