Seedling Tray Sizes Guide
Seedling trays come in different sizes and cell configurations to support the early growth stages of plants. The size of a seedling tray is typically defined by the number of cells it contains, which determines how much space each plant has for root development.
Choosing the correct seedling tray size is important for plant health, nursery efficiency, and transplant success. Different crops require different cell volumes depending on their root systems and growth periods.
In commercial greenhouses and plant nurseries, common seedling tray sizes include 50 cell, 72 cell, 105 cell, 128 cell, and 200 cell trays.
This guide explains the most widely used seedling tray sizes and how to select the right one for your plants.
Common Seedling Tray Sizes
Seedling trays are generally categorized by the number of cells they contain. Each cell holds a single plant, allowing growers to manage seedlings efficiently.
Below are the most common tray sizes used in horticulture and agriculture.
50 Cell Seedling Trays
50 cell trays contain larger individual cells that provide more room for root growth.
These trays are often used for plants that require a longer nursery stage or stronger root development.
Typical applications include:
tomatoes
cucumbers
peppers
eggplants
Because each cell is larger, seedlings can remain in the tray longer before transplanting.
72 Cell Seedling Trays
72 cell trays are one of the most commonly used tray sizes in commercial plant nurseries.
They offer a balance between plant density and root space, making them suitable for many vegetable and flower crops.
Common uses include:
lettuce
cabbage
broccoli
ornamental flowers
72 cell trays are popular because they allow growers to produce many seedlings while still providing sufficient root space.
105 Cell Seedling Trays
105 cell trays are designed for medium-density planting and are often used for crops that require moderate root space.
They are commonly used in greenhouse vegetable production and plant propagation.
Typical crops include:
leafy greens
herbs
small vegetable seedlings
These trays allow growers to maximize production space while maintaining healthy plant development.
128 Cell Seedling Trays
128 cell trays are widely used for high-density seedling production.
Because the cells are smaller, these trays are ideal for plants that are transplanted quickly after germination.
They are commonly used for:
lettuce seedlings
herb seedlings
flower seedlings
This tray size is especially popular in large-scale commercial greenhouses.
200 Cell Seedling Trays
200 cell trays contain very small cells and are designed for starting large numbers of plants in a compact area.
They are often used for:
small leafy vegetables
herbs
microgreens
early stage transplant seedlings
Because the cells are small, seedlings are usually transplanted quickly after germination.
Standard Tray Dimensions
Although the number of cells varies, most commercial seedling trays follow standard external dimensions to fit greenhouse growing systems.
Typical tray size:
540 mm × 280 mm (21.3 × 11 inches)
This standardized size allows trays to fit into nursery racks, greenhouse benches, and automated transplanting systems.
How to Choose the Right Seedling Tray Size
Selecting the right tray size depends on several factors.
Plant Type
Plants with larger root systems require trays with fewer cells and larger volumes.
For example:
fruiting vegetables need larger cells
leafy greens can grow in smaller cells
Nursery Period
The longer seedlings remain in the tray, the larger the cells should be.
Larger cells provide more space for root development and reduce transplant stress.
Growers who need to produce large quantities of seedlings may choose trays with higher cell counts to maximize greenhouse space.
Production Efficiency
Seedling Tray Size Comparison
Different tray sizes serve different production goals.
General guidelines:
50 cells → large vegetables
72 cells → general vegetable seedlings
105 cells → medium-density crops
128 cells → leafy vegetables and flowers
200 cells → high-density seed starting
Understanding these differences helps growers optimize plant health and nursery efficiency.
Conclusion
Seedling tray sizes play an important role in successful plant propagation.
From large 50 cell trays to high-density 200 cell trays, each size is designed to support specific crops and production methods.
By selecting the right seedling tray size, growers can improve germination success, promote healthy root development, and increase overall nursery efficiency.
Frequently Asked Questions
What is the most common seedling tray size?
The most commonly used seedling tray sizes are 72 cell and 128 cell trays. These provide a good balance between plant density and root development, making them suitable for many vegetable and flower crops.
What plants use 72 cell seed trays?
72 cell trays are commonly used for vegetables such as lettuce, cabbage, broccoli, and many ornamental flowers.
What is the difference between 72 cell and 128 cell trays?
72 cell trays have larger cells that allow plants to grow longer before transplanting.
128 cell trays have smaller cells and are typically used for seedlings that will be transplanted earlier.
How do I choose the right seed tray size?
The best tray size depends on the plant type, root development needs, and how long the seedlings will stay in the tray before transplanting.