If you’re planning a garden or buying seedlings, you’ve likely asked, how many plants in a flat? The number of plants in a flat varies significantly by species, container size, and the nursery’s potting practices. There is no single universal answer, but understanding the common standards will help you plan your purchase and your garden space effectively.
A flat, also called a tray or pack, is a shallow plastic container that holds multiple individual plants. They are the standard unit for selling annual flowers, vegetables, and herbs. Knowing what to expect prevents you from overbuying or underbuying for your project.
How Many Plants In A Flat
This core question depends on the size of the individual cells within the flat. Nurseries use different cell counts to suit different plant types and growth stages. The most common configurations are based on the total number of cells in the tray.
Here is a breakdown of the standard flat sizes and their typical plant counts:
- Standard 1020 Flat: This is the most common tray size, measuring approximately 10 inches by 20 inches. It acts as a carrier for smaller insert trays.
- 48-Cell Flat: Often used for larger annuals and vegetable starts like tomatoes or peppers. You get 48 individual plants.
- 36-Cell Flat: Provides more soil space per plant than a 48-cell. Common for mid-size bedding plants.
- 24-Cell Flat: Used for even larger starts, such as certain perennials or robust vegetable seedlings.
- 18-Cell Flat: These are for substantial plants that need room to develop before sale, like large annual vinca or bigger herbs.
- 12-Cell Flat: Often called a “jumbo pack,” this is for the largest starter plants available in a flat format.
- 6-Cell Pack: Typically a standalone pack, but sometimes placed in a flat carrier. For very large vegetable plants.
- Market Packs: These are smaller, consumer-ready units, often holding 4, 6, or 8 plants in a single rigid plastic pack.
Industry Standards And Variations
While the cell counts above are typical, there is no strict enforcement. A grower might use a 50-cell insert instead of a 48-cell. The plant variety also influences the choice. Fast-growing flowers like petunias are often sold in 48 or 36-cell flats, while slower-growing herbs might be in 18-cell trays.
Always check the label or ask the nursery staff. The flat should be clearly marked. If it’s not, you can usually count the cells visually. Remember, a “flat” refers to the full 10×20 tray, while a “pack” might refer to a smaller, segmented unit within it or sold separately.
Why Cell Size Matters More Than Just Count
The cell count tells you how many plants, but the cell volume tells you about the plant’s root development. A 48-cell flat has much smaller individual soil compartments than a 24-cell flat. This impacts how quickly the plant will become root-bound and how soon you need to transplant it after purchase.
Plants from smaller cells are younger, cheaper, and may need more care initially. Plants from larger cells are more established, cost more, and can tolerate more stress right away. Your choice depends on your timeline and gardening experience.
Calculating for Your Garden Beds
To figure out how many flats you need, you must know your garden’s square footage and the recommended spacing for each plant. For example, if marigolds are spaced 10 inches apart and you’re buying a 48-cell flat, one flat will cover a significant area.
Do the math: Sketch your bed, note the spacing, and divide by the number of plants per flat. It’s better to buy one extra flat than to run short, as you can always use extra plants in containers.
Factors Influencing Plant Count Per Flat
Several key factors determine why a flat of pansies has a different number of plants than a flat of tomato seedlings. Understanding these helps you make informed purchases.
Plant Species And Growth Habit
Fast-growing, spreading annuals like alyssum or lobelia are perfect for high-density flats (like 48 or 72 cells). They establish quickly and don’t mind being a bit crowded initially. Larger, single-stem plants like zinnias or celosia need more space from the start, so they are grown in 36 or 24-cell flats.
Vegetables follow a similar rule. Lettuce and kale can be grown in 72-cell flats. Tomatoes, peppers, and eggplants, with their larger root systems, are almost always in 48-cell or larger packs. Herbs like basil do well in 38-cell flats, while rosemary or lavender cuttings might start in 72-cells.
Nursery Potting Practices And Automation
Most commercial nurseries use automated potting machines. These machines are set up for specific tray inserts. The cost and efficiency of using a 48-cell insert versus a 36-cell insert influence what they choose for a crop. It’s a balance of space, soil cost, and plant health.
Some local growers may pot by hand, leading to more variation. They might use whatever trays they have reused from previous seasons. This is why asking directly is always a good idea.
Regional Differences And Supplier Choices
In different parts of the country, standard flat counts can vary slightly. A wholesale supplier on the East Coast might default to 48-cell flats for impatiens, while a West Coast grower might use 36-cells. Big-box stores often have contracts with growers for specific pack sizes, which may differ from your local garden center.
This regional variation is minor but worth noting if you move or order plants online from a distant nursery. Their product description should specify the cell count.
How To Determine The Count For Your Specific Flat
Don’t guess. Use these simple methods to know exactly what you’re buying.
Visual Inspection And Counting Cells
The most straightforward method is to look at the flat. Gently part the plant foliage and count the number of distinct square or round compartments. They are usually arranged in a grid pattern. A full 1020 flat holding 48 cells will have a grid of 6 cells by 8 cells.
If the plants are very large and leafy, you may need to lift one gently to see the cell divider. Be careful not to damage the roots.
Reading Plant Tags And Flat Labels
Always check the plant tag. Many modern tags include a pack size notation, such as “48 plants per flat” or “Packed in 4″ pots.” The label on the flat itself, often on the short end, might have a stamped code indicating the insert type, like “F-48” for a 48-cell insert.
If the information isn’t printed, the price point can be a clue. A flat priced at $18 is likely a different cell count than one priced at $28 for the same plant type.
Asking Nursery Staff Or Growers
Never hesitate to ask. Nursery staff deal with these questions daily and can tell you the cell count immediately. They can also advise if that size is appropriate for your planting timeline. For instance, they might suggest a 24-cell flat over a 48-cell if you plan to transplant next week versus today.
At a farmers’ market, you can ask the grower directly about their potting practices. They often have the most detailed knowledge.
Planning Your Purchase: From Flats To Garden
Turning flats of seedlings into a beautiful garden requires a bit of planning. Here is a step-by-step guide.
Step 1: Measure Your Planting Area
Use a tape measure to find the length and width of your garden bed in feet. Multiply them to get the square footage. For a 10-foot by 4-foot bed, you have 40 square feet to fill.
Step 2: Check Plant Spacing Requirements
On the plant tag or seed packet, find the “spacing” recommendation. This is usually the minimum distance needed between plants for proper growth. Note this number in inches.
Step 3: Calculate Plants Needed Per Square Foot
You can use a simple formula. If spacing is 12 inches, you need 1 plant per square foot. If spacing is 6 inches, you need 4 plants per square foot. Online garden spacing calculators can do this math for you quickly.
Step 4: Factor In Your Flat’s Plant Count
Divide the total number of plants you need by the number of plants in your chosen flat. For example, if you need 80 plants and are buying 48-cell flats, you’ll need 1.66 flats. Round up to 2 flats.
Step 5: Account For Extras And Losses
It’s wise to add 10% to your total for plants that fail, get damaged, or to fill in gaps. Having a few extra is always better than having a hole in your design.
Common Plant Types and Their Typical Flat Counts
To give you a practical reference, here are common plants and the flat sizes they are most frequently sold in.
Annual Flowers
- Petunias, Impatiens, Marigolds: Very commonly in 48 or 36-cell flats.
- Geraniums, Pansies, Violas: Often in 36-cell or 24-cell flats due to their size.
- Alyssum, Lobelia, Sweet Potato Vine: Often in high-density 72-cell or 48-cell flats.
Vegetable Seedlings
- Tomatoes, Peppers, Eggplants: Almost exclusively in 48-cell or larger packs (6-packs are very common).
- Lettuce, Kale, Swiss Chard: Frequently found in 72-cell or 48-cell flats.
- Cucumbers, Squash, Melons: Usually in individual pots or 6-cell packs due to rapid growth.
Herbs And Ground Covers
- Basil, Cilantro, Parsley: Typically in 36-cell or 48-cell market packs.
- Thyme, Oregano, Mint: Often in 18-cell or 24-cell flats as they are slower growing.
- Ivy, Pachysandra, Vinca Minor: For ground covers, high-density 72-cell or 128-cell “plugs” are common.
Cost Implications of Different Flat Sizes
The price of a flat is not just about the number of plants. It reflects the age of the plant, the amount of soil used, and the time it occupied nursery space.
A 48-cell flat of petunias will have a lower price per flat than a 24-cell flat of the same variety. However, the price *per plant* might be similar, or the plants in the larger cells might cost more each because they are more mature. You are paying for a head start on the growing season.
Consider your budget and goals. If you are planting early and have time to nurture smaller plants, high-cell-count flats offer great value. If you need instant impact or are planting late in the season, paying more for larger cells is a smart investment.
FAQ Section
How Many Plants Are Usually In A Flat?
The most common numbers are 48, 36, 24, 18, and 12 plants per standard 10×20 flat. The exact count depends on the cell tray insert used by the grower.
What Is The Standard Flat Size For Plants?
The standard industry flat is called a “1020,” measuring roughly 10 inches by 20 inches. It is a shallow tray used to hold smaller cell packs or inserts.
How Many Square Feet Does A Flat Of Flowers Cover?
Coverage depends entirely on plant spacing. A 48-cell flat of plants spaced 8 inches apart can cover about 16 to 20 square feet. Always calculate based on the specific plant’s needs.
Is It Cheaper To Buy Plants In Flats?
Yes, buying in flats is almost always cheaper per plant than buying individual pots. Flats are the wholesale-like option for gardeners planting in larger quantities.
How Many Plants In A 1020 Tray?
A 1020 tray itself doesn’t hold soil; it holds inserts. The insert determines the count. Common inserts for a 1020 tray hold 72, 48, 36, 24, or 18 plants.
Conclusion
So, how many plants in a flat? As you’ve seen, the answer is variable but knowable. The standard 1020 flat can hold from 12 to 72 plants, with 48 being a very common count. The key is to look past the flat and at the cell size, as this tells you more about the plant’s readiness.
Always check labels, count cells, or ask for help. Use the plant count to accurately calculate your garden needs, ensuring you buy the right amount for your space. With this knowledge, you can shop for flats confidently, making the most of your budget and your gardening efforts. Your garden will thank you for the careful planning.