Introduction
There is a unique kind of excitement that comes with planning a summer garden. Walking through a garden center or browsing a catalog, the vibrant colors of begonias promise a season filled with lush foliage and constant blooms. Whether you are envisioning a tidy border along a shaded walkway or a massive splash of color in a garden bed, begonias are a reliable and beautiful choice. At Longfield Gardens, we enjoy helping gardeners find the perfect balance between quantity and quality to ensure every planting project is a success.
When you start planning your layout, one of the first practical questions you will likely ask is how many plants come in a flat of begonias. This answer is essential for budgeting your time and money, as well as for ensuring you have enough plants to fill your space without having too many left over. Knowing the standard counts and pot sizes allows you to map out your garden with confidence.
This article covers everything you need to know about begonia flats, from standard industry quantities to calculating the exact number of plants you need for your specific square footage. We will help you understand the differences between wax begonias and tuberous begonias so you can choose the best option for your landscape. By the end, you will be ready to head to the garden center or order your favorites with a clear plan in mind.
Understanding the Standard Nursery Flat
In the gardening world, a "flat" is more than just a tray of plants; it is a standardized unit of measurement used by professional growers and retailers. The most common tray used in the United States is known as the "1020 tray." This name comes from its approximate dimensions: 10 inches wide by 20 inches long. While the outer dimensions of the tray stay the same, the number of plants inside can vary significantly based on the size of the individual plastic cells or pots.
When you ask how many plants are in a flat of begonias, the answer depends on the size of the containers the grower used. Most garden centers sell begonias in "cell packs." These are plastic inserts that fit into the 1020 tray. A cell pack might hold three, four, or six individual plants. The more plants there are in a flat, the smaller each individual plant will be.
It is helpful to think of a flat as a puzzle. The tray is the frame, and the cell packs are the pieces. If the pieces are large, fewer will fit in the frame. If the pieces are small, you can fit quite a few more. This variety allows gardeners to choose between buying many small plants for a large area or fewer, more established plants for a smaller space or container.
Common Plant Counts for Begonia Flats
While there is no single "official" number of plants per flat, the industry generally adheres to a few common configurations. When you go to buy your begonias, you will likely see one of the following counts:
The 18-Count Flat
An 18-count flat usually consists of 18 individual pots that are roughly 3.5 to 4 inches wide. These are often referred to as "4-inch specials." Because these plants have more room for their roots to grow, they are typically larger and more established than those found in higher-count flats. These are excellent if you want an immediate impact in your garden or if you are planting later in the season and want the begonias to fill in quickly.
The 24-Count Flat
A 24-count flat is a very common size for bedding begonias. This configuration often consists of four "6-packs." Each 6-pack contains six small cells. This is a great middle-ground option for gardeners. You get two dozen plants, which is usually enough to cover a decent-sized border or a few large patio containers.
The 32-Count or 36-Count Flat
These are perhaps the most standard "bedding plant" flats. A 32-count flat typically holds eight packs of four plants each. A 36-count flat holds six packs of six plants each. These plants are smaller and are meant to be planted in mass. If you have a large area to cover, such as a backyard flower bed, these higher-count flats offer the best value per plant.
The 48-Count Flat
A 48-count flat is often the most economical choice. It consists of 12 packs of four plants each. These plants are quite small when you buy them and will require a bit more patience as they establish themselves in the soil. However, begonias are vigorous growers, and these small starts will often catch up to their larger counterparts within a month of warm weather.
Key Takeaway: The number of begonias in a flat depends on the pot size. Smaller pots mean more plants per flat (up to 48), while larger pots mean fewer plants (usually 18).
Why the Count Matters for Your Garden
Choosing the right flat size is about more than just the number of plants; it is about the health and "settling in" period of your garden. Smaller plants in a 48-count flat are younger. They often experience less "transplant shock," which is the stress a plant feels when moving from a pot to the ground. Because their root systems are smaller, they can adapt quickly to the new soil.
On the other hand, larger plants from an 18-count flat have a more developed root system and more foliage. They provide instant color, which is a major advantage if you are hosting a garden party or an outdoor event in the near future. They are also more resilient against pests like slugs, as they have more leaves to spare than a tiny seedling.
When we evaluate plants in our trial garden at Longfield Gardens, we look at how quickly different sizes establish. We have found that while larger starts look better on day one, smaller starts often develop a more robust root system in the long run because they weren't "root-bound" (where roots grow in circles around the inside of a pot) in the nursery.
Calculating How Many Flats You Need
To determine how many flats of begonias you should buy, you need to perform a little bit of "garden math." This starts with knowing the square footage of your planting area and the recommended spacing for the type of begonia you have chosen. For help planning timing around your climate, see our Shipping Information.
Step 1: Measure Your Space
Measure the length and width of the area you want to plant. Multiply these two numbers to get the total square footage. For example, a rectangular border that is 10 feet long and 2 feet wide is 20 square feet.
Step 2: Determine Spacing
Begonias are generally planted between 6 and 12 inches apart.
- 6-inch spacing: For a dense, carpet-like look.
- 8-inch spacing: The standard for most bedding wax begonias.
- 12-inch spacing: For larger tuberous varieties or if you are willing to wait for them to spread.
Step 3: Use a Spacing Factor
To find the number of plants needed per square foot, you can use these simple estimates:
- 6-inch spacing: 4 plants per square foot.
- 8-inch spacing: 2.25 plants per square foot.
- 12-inch spacing: 1 plant per square foot.
An Example Calculation
If you have a 20-square-foot area and you want to plant wax begonias at 8-inch spacing, you would multiply 20 (square feet) by 2.25 (plants per square foot). This equals 45 plants. If your local garden center sells 24-count flats, you would need two flats to complete your project.
What to do next:
- Measure your garden beds before heading to the nursery.
- Decide if you want a "full" look immediately (closer spacing) or are happy to wait (wider spacing).
- Always buy a few extra plants to account for any accidental damage during transplanting.
Wax Begonias vs. Tuberous Begonias in Flats
It is important to note that not all begonias are the same, and this affects how they are sold. The begonias you most often find in large flats are Wax Begonias (Begonia x semperflorens-cultorum). These are fibrous-rooted plants with succulent stems and waxy leaves. They are prolific bloomers and stay relatively compact, making them the classic choice for "flat" sales. If you want a broader overview, All About Begonias is a helpful place to start.
Tuberous Begonias (Begonia x tuberhybrida) are different. These grow from a potato-like tuber. While you can sometimes find them pre-started in flats, they are more commonly sold as individual plants in larger 4-inch to 6-inch pots, or as dormant tubers. Tuberous begonias have much larger, more dramatic flowers and often have a trailing habit.
If you are buying tuberous begonias in a flat, the count will almost always be lower—typically 18 or even 12—because these plants need more space for their large leaves and heavy blooms. Because they grow larger, you also need fewer of them to fill a square foot compared to wax begonias.
How to Choose the Best Flat of Begonias
When you are standing in front of a rack of plant flats, it can be tempting to just grab the first one you see. However, taking a minute to inspect the plants will ensure you get the best value and the healthiest garden.
Look at the Foliage
The leaves should be a deep, healthy green (or bronze, depending on the variety). Avoid flats where the leaves look yellow, spotted, or wilted. While begonias are tough, starting with stressed plants means they will take longer to begin blooming in your yard.
Check for "Leggy" Growth
A "leggy" plant is one that has grown very tall and thin because it wasn't getting enough light. These plants can be floppy and weak. Look for begonias that are short, bushy, and compact. These have been grown in the proper light and will have stronger stems. For more on variety-specific light needs, see Are Begonias a Shade Plant?
Inspect the Roots
If the garden center allows, gently lift one plant out of its cell. The roots should be white and visible throughout the soil, but they should not be a solid, swirling mass of brown. If the roots are circling the bottom of the pot tightly, the plant is "root-bound." You can still plant it, but you will need to gently break up the root ball with your fingers to encourage the roots to grow outward into your garden soil.
Flowers Aren't Everything
It is a common instinct to choose the flat that is covered in the most open flowers. However, it is actually better to choose a flat with lots of unopened buds. A plant that is in full bloom is putting all its energy into the flowers. A plant with buds is ready to put its energy into growing new roots once it hits the ground, leading to a much stronger plant in the long run.
Tips for Successful Transplanting
Once you have your flats home, the goal is to get them into the ground as efficiently as possible. Timing and technique are the two biggest factors in how well your begonias will thrive. For seasonal planning, When Do You Plant Begonias? is a useful guide.
Timing Your Planting
Begonias are tropical plants. They love warmth and have zero tolerance for frost. Wait until the danger of frost has completely passed and the soil has warmed up. In most regions, this is a few weeks after the last frost date. If the soil is too cold, the begonias will simply sit there and not grow, or their stems may become mushy.
Preparing the Soil
Begonias prefer soil that is rich in organic matter and drains well. "Drainage" refers to how fast water leaves the soil. If you have heavy clay soil that stays soggy, the begonias may struggle. You can improve drainage by mixing in some compost or peat moss before you plant.
The Planting Process
- Water the flat first: It is much easier to remove plants from a cell pack when the soil is moist.
- Dig a small hole: The hole should be just deep enough so the top of the plant's root ball is level with the surrounding soil.
- Gently squeeze the cell: Do not pull the plant by the stem. Squeeze the bottom of the plastic cell to pop the root ball out.
- Set and snug: Place the plant in the hole and gently press the soil around it to remove any large air pockets.
- Water deeply: Give the new transplants a good soak immediately after planting to help settle the soil.
Designing Your Space with Begonia Flats
Using begonias in mass is one of the most effective ways to create a high-impact garden. Because they are so consistent in height and color, they work beautifully in patterns and borders.
If you are using a 36-count flat of wax begonias, you might consider a "staggered" planting pattern. Instead of planting them in straight rows like soldiers, plant them in a zigzag or "W" pattern. This covers the ground more effectively and hides the bare soil much faster. For more spacing ideas, How Wide Do Begonias Grow? can help with planning.
For a classic look, try bordering a bed of taller flowers with a row of begonias from a flat. White-flowered begonias with green leaves look crisp and clean against a green lawn, while bronze-leafed varieties with red flowers offer a warm, dramatic contrast. We often suggest mixing colors within a flat if you want a "cottage garden" feel, or sticking to a single color for a more formal, modern aesthetic.
Key Takeaway: Using a staggered planting pattern with begonias from a flat creates a lush, professional-looking landscape that fills in quickly.
Cost Considerations: Flats vs. Individual Pots
One of the main reasons gardeners ask how many plants are in a flat of begonias is to compare prices. Buying by the flat is almost always more cost-effective than buying individual pots.
Retailers often offer a "flat price" that is discounted compared to buying the same number of cell packs individually. For example, if a 6-pack costs $5.00, but a full flat of six 6-packs (36 plants) costs $25.00, you are essentially getting one pack for free.
If you have a very small space, such as a single window box, a full flat might be too much. In that case, buying just one or two cell packs is the way to go. But for most landscape projects, the flat is the superior value. Begonias are also excellent fillers for containers; if you have leftover plants from your garden beds, you can always tuck them into the edges of large pots containing hibiscus or other upright shrubs. For related planting ideas, you can browse the Begonia Hanging Begonias collection.
Caring for Your Begonias After Planting
Begonias are famously "low-maintenance," but a little bit of care will keep them blooming until the first frost of autumn. The beauty of these plants is that they are "self-cleaning," meaning they drop their old flowers on their own, so you don't have to spend hours "deadheading" (removing spent blooms). For a care overview, see How to Care for Begonia Plant.
Watering Wisely
Begonias have succulent stems that store water, which makes them somewhat drought-tolerant. However, they perform best when the soil is kept consistently moist but not soggy. A good rule of thumb is to water when the top inch of soil feels dry to the touch. If you are growing them in pots, they will need water more frequently than those in the ground.
Feeding for Flowers
While begonias aren't heavy feeders, a light application of a balanced, water-soluble fertilizer every few weeks can help sustain their bloom production. This is especially helpful for plants in flats that may have used up the nutrients in their small amount of potting soil before you bought them.
Light Requirements
Check the label on your flat, as light needs vary by variety. Most wax begonias can handle anything from part shade to full sun, though in very hot climates, they appreciate some afternoon shade. Tuberous begonias almost always prefer filtered light or shade, as their delicate flowers can scorch in intense midday sun.
Summary of Begonia Flat Quantities
To wrap up, the number of plants you get in a flat is tied to the size of the container. Here is a quick reference for what to expect:
- 18 Plants: Large 3.5" to 4" pots. Best for instant impact and large containers.
- 24 Plants: Standard 6-packs. A great all-purpose choice for borders.
- 32-36 Plants: Small 4-packs or 6-packs. The most economical choice for large garden beds.
- 48 Plants: Very small cells. Ideal for high-volume planting on a budget.
At Longfield Gardens, we want your gardening experience to be as rewarding as possible. By understanding these quantities and how they translate to your specific garden space, you can eliminate the guesswork and focus on the joy of watching your garden grow. If you are still comparing options, the Begonia Hanging Begonias collection and our Learn hub are good next stops.
Final Steps for Success:
- Confirm your garden's square footage and desired spacing.
- Choose the flat size that matches your budget and timeline.
- Inspect plants for healthy roots and plenty of unopened buds.
- Plant in warm soil and water deeply to ensure a beautiful season of color.
FAQ
Is it cheaper to buy begonias by the flat?
Yes, buying a full flat is almost always more economical than buying individual cell packs or pots. Most retailers offer a bulk discount when you purchase a full 1020 tray, making it the best option for large landscaping projects or filling multiple containers.
How many wax begonias do I need for a 10-foot border?
If your border is 1 foot wide (10 square feet) and you plant them at the standard 8-inch spacing, you will need about 23 plants. A single 24-count flat would be perfect for this project, providing enough plants to fill the space with a few extras for corners. For planting timing, the Shipping Information page can help you match your order to your zone.
Can I mix and match different colors in one flat?
This depends on the retailer. Some garden centers sell "mixed" flats that already contain a variety of colors, while others require you to buy a full flat of a single color. If the retailer sells individual cell packs, you can often "build your own" flat by mixing different colors into a single tray. For more begonia basics, Are Begonias Annuals? is a helpful reference.
How long can I keep begonias in the flat before planting?
While it is best to plant them as soon as possible, you can keep begonias in their flats for a week or two if necessary. Keep them in a shaded, sheltered spot and check them daily for water, as the small amount of soil in the cells dries out very quickly. If you need extra guidance on site selection, Where to Plant Begonias offers more detail.
