7 Best Seedling Starter Trays in 2020

To help you choose the best seedling starter trays for growing plants from seeds at home, we’ve compiled a list of the top-performing seedling trays on the market. In the course of over a dozen hours of research and testing, we consulted seasoned home gardeners and horticulture experts, compared reviews and examined the specifications of the products that we found. We considered specs including materials, humidity control, and a number of cells. Finally, we considered whether the seed starting trays were made of plastic, silicone, or biodegradable fiber and whether the trays came with a dome for moisture control.

Our top pick, the 9GreenBox 144 cell, is among the best seedling starter trays for home use. It comes with a generous 144 cells arranged in convenient, stackable 6-cell trays, plus it has a flexible and durable seed plugs for easy seedling removal. Read on for more of the best seedling trays on the market.

Top 7 Best Seedling Starter Trays

 #1  9GreenBox 144 Cell Seedling Starter Trays

Award: TOP PICK

WHY WE LIKE IT: These seedling trays pack the same amount of seedling space as two standard 72 cell flats, but in a more convenient and flexible configuration, with 24 sets of 6-cell trays. The seed plugs are flexible and won’t crinkle or get stuck easily, making it a breeze to remove seedlings for transplanting.

Pros
  • Built-in drain holes running throughout
  • Ideal cell size for indoor room temperature germination
  • Comes with five plant labels
Cons
  • Doesn’t offer a dome for humidity control

Packaged more conveniently for indoor seed starting than the typical wide flat seedling trays, this 144-cell kit makes it easier to start seeds even if you don’t have a huge amount of tabletop or floor space. The cells are thin-walled for temperature propagation yet durable enough that you can easily remove seedlings without breaking them.

While it doesn’t have a dome lid for humidity control, it does carry out the main function of a seed starting tray, making it easier to grow plants from seeds at room temperature. These trays work with any growing medium and each cell has a drain hole. These trays will be perfect to use in your lawn and garden.

 #2  MIXC Humidity Adjustable Seedling Starter Trays

Award: HONORABLE MENTION

WHY WE LIKE IT: Seed germination trays with dome included so you can provide a controlled humidity environment for better germination of plant species’ whose seeds require moist soil. The domes have vents that let you fine-tune the humidity for any different type of plant.

Pros
  • Vents allow for excellent moisture control
  • Comes with a watertight base tray
  • Suitable for most small-seeded flowering plants, fruits, vegetables and herbs
Cons
  • Fewer cells in the kit than you get with some seed trays
  • No seedling heat mat included

Among seed starting trays with dome included, these are extra convenient for indoor seed starting since the domes have adjustable vents that let you change the humidity so that it’s suitable for different kinds of plants. These trays give you something of a mini greenhouse for growing plants and flowers, especially useful for varieties of plants that require high humidity for starting seeds in plug trays.

The soil blocks in this kit come in trays with 12-cells each, and you get 10 trays per order. The kits also include plant labels and a useful watertight base tray. Like most high-quality seed starting systems, each cell in the tray has a drain hole to avoid saturation. For more of your gardening needs, you should also read our guide to the best garden root slayer.

 #3  Industry Standard Grower’s Supply Seedling Starter Trays

Award: LARGEST QUANTITY

WHY WE LIKE IT: This seedling starter kit comes with a whopping 720 cells, packaged conveniently as a stack of 120 6-cell seedling trays for flexible home growing.

Pros
  • Soil blocks ideally sized for flowering herbs
  • Drain holes in each cell to avoid waterlogging
  • Flexible soil plugs make transplanting easy
Cons
  • No under tray included
  • Doesn’t come with moisture-controlling dome

With these seedling trays, wholesale quantities of cells and flexible tray arrangements are among the main selling points. Aimed at experienced home gardeners, these horticulture grade seedling starter trays have flexible yet durable walls that make it easy to transplant seedlings.

Configured in 6-cell trays, each cell measures 1.5 inches square by 2.25 inches deep, which is generally considered ideal for room temperature germination in the largest number of common flowering herb and decorative plant species. The kit also comes with handy plant labels included, though there is no undertray or moisture-controlling dome. For decorating the inside of your home you should also read our guide to the best artificial plants. 

 #4  AAAmercantile Seed Starter Trays

Award: BEST HEAD START FOR REPOTTING

WHY WE LIKE IT: These seed starter trays have larger 2.5 inch square by 3 inch deep cells that help give seedlings a head start before transplantation, allowing for larger roots.

Pros
  • Allows for more growth before transplanting
  • Can be used for types of plants with larger seeds thanks to larger cells
  • Comes with 15 stake labels
Cons
  • Fewer cells than most other seedling trays
  • Larger cell size can make germination more difficult for temperature-sensitive seeds

Excellent for plants with larger seeds and a good choice if you’re looking for seedling starter trays that allow for more root growth and give plants a head start before repotting, these six cell trays come with oversized cells that are three inches deep and 2.5 inches square, as opposed to the more common seedling size of 1.5 inches square by 2.25 deep.

This kit comes with 15 trays, giving you 90 cells in total. Like most of the seedling trays out there, these are made from lightweight flexible plastic, making it easy to remove seedlings for transplanting. While not as easy to reuse as some of the dedicated reusable seed starting trays, they can be used more than once if you’re careful when depotting. For the rest of your gardening needs, you should also read our guide to the best wheelbarrow.

 #5  AngtuoSeed Starter Peat Pots Seedling Starter Trays

Award: BEST SUSTAINABLE

WHY WE LIKE IT: These eco-friendly and biodegradable peat pots make transplanting easy and promote aeration and root growth, while at the same time reducing waste and environmental impact.

Pros
  • Absorbs into soil for easy transplanting
  • Promotes root growth through better soil aeration
  • Ships with 20 plant markers
Cons
  • Not packaged in a convenient tray form
  • Less tidy for indoor use than plastic or silicone seedling starter trays

These peat pots are easier to transplant from than typical plastic seedling starter trays, since there’s no need for depotting, you can just plant the entire cell, seedling, peat pot and all. The pot naturally becomes part of the soil, adding helpful soil aeration and nourishing the root system.

More eco friendly than typical plastic seedling starter trays, these peat pots help reduce waste and pollution, since there’s nothing to throw away. Each pot is breathable so the soil gets aerated well for germination, and while they don’t have drain holes, you can easily poke a drain hole to help manage moisture. These permeable seedling pots can be used with the best propagation trays, too. When placed close together they let root systems connect between adjacent cells. For the rest of your lawn, you should also take a look at our guide to the best riding lawn mower.

 #6  Soligt 3-Set Strong Plant Seedling Starter Trays

Award: BEST MOISTURE CONTROL

WHY WE LIKE IT: This seed germination tray with dome and watertight under-tray does a great job of managing humidity for indoor seed starting. It works especially well with plants that need higher humidity for germinating from seeds.

Pros
  • Clear vents for maximum light penetration
  • Each tray fits 48 standard 1.5 x1.5 inch cells
  • Watertight base
Cons
  • Seedling cells not included
  • Does not allow for much temperature control

These seedling starter trays are great for home gardeners looking to grow plants from seeds that require moist or humid environments for successful germination. They come with watertight under-trays that make them convenient for use indoors or out. The included dome lids form a tight seal with the trays, helping to regulate moisture.

The domes have two vents each and are adjustable so that you can fine-tune the humidity, creating a mini-greenhouse for seed starting. These sets don’t come with cells included, so you have to buy those separately, but if you’re looking for the humidity control for your seedling starter tray, they’re a must-see.

 #7  Window Garden Seedling Starter Trays

Award: BEST ON A BUDGET

WHY WE LIKE IT: These complete kits include 3 10-cell seed starting trays with a dome, each one is just 10” by 4”, allowing them to fit on a standard windowsill, making them great for indoor gardening. They come with waste-free, biodegradable fibrous seedling cells for easy replanting.

Pros
  • Organic plug compartments for easy replanting
  • Biodegradable mesh cells support air pruning of root systems
  • Humidity controlled
Cons
  • Too small for standard size horticulture seedling cell trays

These small window ledge seedling trays include a dome for easy humidity control, plus they come with organic soil plugs that, similar to the more common peat pots, allow for easy replanting, meaning you don’t have to take seedlings out of their cells since the cells are biodegradable and nourishing.

These cells also have a mesh layer that supports air pruning of root systems, helping roots to grow stronger and more able to absorb nutrients from the soil. The soil plugs included in the kit are organic and have a low sodium content. Each tray fits 10 36-mm seedling cells. Their convenient size and easy replanting make these seedling starter trays great for beginners and for teaching kids.

How We Decided

In order to choose the best seedling starter trays for successful seed germination in a variety of plant types, we looked for quality materials and components, horticulture industry-standard sizes, convenient packaging, and good moisture control.

We gave preference to starter trays that included a large number of cells, great for horticulturists, home gardeners or hobbyists starting an herb garden or growing decorative indoor plants from seeds. For versatility, we primarily went with the common 1.5 x 1.5 x 2.25-inch size, since this is a good compromise between root system depth and temperature control for many common seed types.

We also gave a bonus to biodegradable seed trays and peat pots that could be planted along with the seedlings, since this adds to the aeration of the soil. It also helps avoid plastic waste.

We limited our choices to seedling starter trays with good drainage, either from drain holes in each cell or by means of cells constructed from breathable materials, such as peat pots.

Best Seedling Starter Trays Buyer’s Guide

Features to Consider

  1. Cell Size
    When selecting a seedling germination tray make sure to pick the right size for the seeds or shoots you’re trying to grow. Most small seed flowers, fruits, and herbs germinate well in cells about 1.5 x 1.5 x 2.25 inches. For larger root systems, consider a deeper celled seedling starter tray.
  2. Humidity Dome
    Seed starting trays with dome lids help maintain a constant desirable humidity level that helps many types of plants grow from seeds. For better control, look for a dome with adjustable vents so you can fine-tune the humidity.
  3. Reusable Tray
    When growing seedlings, especially indoors and when using biodegradable cells, watertight, reusable seed starting trays help maintain water balance and also help keep the indoor garden clean and tidy.
  4. Cell Material
    While a thin, flexible plastic is the most common material for seedling starter trays, you can also find silicone seed starting trays and organic, fibrous seedling cells that merge with the soil after replanting.
    Silicone trays are great for use with grow lights or a seedling heat mat for temperature control, and they are typically more durable than plastic trays. Organic seedling cells, such as peat pots, are eco friendly and have some advantages such as air pruning, leading to stronger root systems in many plants.

Seedling Starter Trays FAQs

What is the best seed starter?

Depending on the type of plant you’re looking to grow, the best seed starter may be a biodegradable peat pot, a humidity-controlled seedling tray with dome lid or a silicone tray for use with a heat mat for precise temperature control.

How do you use seed starter trays?

Seed starter trays are designed to hold just enough soil to give small seeds a chance to germinate in well-aerated, room temperature soil. Once the seedlings have grown and the roots begin to reach the edge of the cell, you typically replant them in a larger pot or in the ground in the desired location.

Why are seeds often started in plug trays?

Plug trays allow for some advantages when starting growing plants from seeds, including the ability of the mesh soil plugs to promote air pruning, supporting healthy root systems. These soil plugs also make it easy to replant the seedlings and are great for the propagation of new offshoot plants from buds and stems.

How do you make seedling trays at home?

You can make biodegradable seedling trays by measuring the desired size, usually somewhat larger than the cells of a baking pan for muffins, and using peat moss along with a biodegradable cloth mesh to form the walls of the cells.

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Ryan Mcbride

Ryan McBride is a writer based in Los Angeles. He has contributed work to magazines and sites including Gayot, Spy, Paper, Ladygunn, 3AM and the Crab Creek Review. He writes consumer reviews, essays, science and tech journalism as well as literary and art criticism.

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