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Published Oct. 8, 2021

Simply dropping some seeds into the garden and hoping that they will take root is certainly one way to approach home gardening, but it isn’t the most effective way to ensure that the seeds will grow. In fact, exposing the seeds to the dangers of the outdoor garden often leads to seeds being eaten by insects, rodents, and other pests.

Instead, start your seeds in a safe, controlled seedling starter tray that can be kept indoors until the seedlings are ready to be transplanted into the garden. The best seedling starter trays come with humidity domes, watering mats, and base trays to help improve the chances of your seeds germinating, without putting them at risk of being eaten by scavengers. Keep reading to learn how to choose the best seedling starter trays for your next home grow.

How We Picked the Best Seedling Starter Trays

Methodology

Years of home gardening experience have helped to form an understanding of what works and what doesn’t work when it comes to seed germination and seedling growth. This experience, combined with extensive research of more than 40 different products, has formed the basis for this selection, with significant emphasis placed on the material, dimensions, and capacity of the seedling starter trays.

There are several different materials used to make these trays, and each one has a different, but equal benefit. I chose top products from each material category, including biodegradable, disposable plastic, and reusable plastic. The dimensions as well as the capacity of the seedling starter trays helped to determine how many plants could be grown at one time without choking out nearby seedlings. Additionally, any product with extra features that improved the germination, sprouting, or growth period was typically considered superior to similar products that lacked these added benefits.

The Best Seedling Starter Trays: Reviews & Recommendations

Best Overall Super Sprouter HGC726403 Deluxe Propagation Kit

Built-In Grow Light

Quickly sprout new seedlings with this comprehensive seedling starter tray kit.

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Why It Made the Cut: Use the built-in grow light and humidity dome to efficiently germinate, sprout, and grow plants.

Specs: 

  • Capacity: Variable up to 72 cells
  • Material: Reusable plastic
  • Dimensions: 10 x 20 inches

Pros:

  • Comes with a grow light and humidity dome
  • Reusable for multiple home grows
  • The tray fits most standard inserts and plug trays

Cons:

  • Does not include a plug tray with individual cells

Ensure that the seeds germinate and sprout quickly with this Super Sprouter Deluxe Propagation Kit. It comes with a humidity dome to help control the humidity level during germination. The seedling starter tray measures 10 by 20 inches, allowing it to be used with most standard inserts and plug trays. Though it should be noted that while this product can accommodate a tray with up to 72 cells, it does not come with a plug tray. Instead, the seedling starter set is made up of a reusable plastic base tray to collect excess water, a humidity dome, and a grow light to provide even lighting to the plants. 

The grow light is designed to sit in a track on top of the humidity dome, where it can shine down on the entire tray. This comprehensive kit is an excellent option for a beginner because it provides the user with all of the basic supplies to start growing their own plants in the comfort of the kitchen, living room, den, or even the bedroom.

Best Value: VpnDiyp 180 Cells Seed Starter Tray

Affordable Value Pack

Germinate and sprout up to 180 seedlings with this impressive bundled product.

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Why It Made the Cut: Use the adjustable vents on each humidity dome to help new seeds germinate quickly.

Specs: 

  • Capacity: 180 cells
  • Material: Reusable plastic and thin disposable plastic
  • Dimensions: Large—14.2 x 10.8 inches; small—7.3 x 5.6 inches

Pros:

  • Comes with tools and labels
  • Three large trays and three small trays
  • Inexpensive, reusable, and easy to store
  • Adjustable air vent on humidity dome

Cons:

  • Humidity dome may be loose or ill-fitting

The VpnDiyp 180 Cells Seed Starter Tray is an impressive product, especially given the 180-cell capacity and the affordable price for this complete set. This seedling starter tray set includes three small trays that each measure 7.3 by 5.6 inches and have a capacity of 12 cells. These base trays also have drain holes, so that excess water is collected by the small base tray.

The set also comes with three large base trays that measure 14.2 inches by 10.8 inches and can each accommodate four 12-cell trays, giving the large trays a capacity of 48 cells each. These trays are covered with humidity domes that have adjustable air vents to help control the humidity. There is some concern about whether the humidity domes are too loose or simply ill-fitting, and the 12-cell trays are made of thin, disposable plastic, so they may need to be replaced. Additionally, this reusable plastic set comes with two gardening tools to help with transplantation, labels for the plants, and a pen to write on the labels.

Best Biodegradable: JOLLY GROW Seed Starter Peat Pots Kit 

Simple Transplantation

Germinate, sprout, and transplant seedlings without having to remove them from the seedling starter tray with this biodegradable product.

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Why It Made the Cut: Ensure that the roots, stem, and leaves are undamaged by poor transplantation with this biodegradable starter tray that can be planted directly into the garden.

Specs: 

  • Capacity: 50 cells
  • Material: Biodegradable peat pots
  • Dimensions: 10 x 4 inches

Pros:

  • Biodegradable cells are easy to transplant
  • Environmentally friendly option for home gardening
  • Five 10-cell trays with plastic plant markers/labels

Cons:

  • Water permeable and doesn’t come with a base tray

One of the main benefits of using a biodegradable seedling starter tray is that the seedlings do not need to be removed from the cells. This makes it simple to break apart the cells and plant them individually in the garden without worrying about potentially damaging the seedling in an attempt to remove them from a plastic tray. Once the biodegradable peat cells are buried, they will begin to break down and the roots of the seedlings will have no issue piercing through the peat walls and spreading into the soil.  

The JOLLY GROW Seed Starter Peat Pots Kit comes with five trays that each have 10 cells for a total capacity of 50 cells. Each tray measures 4 by 10 inches and also includes plastic plant markers so that the cells can be labeled with the name of the plant. Just keep in mind that the biodegradable cells, while great for the environment, are water-permeable, so it’s advised to have a non-permeable base tray to collect excess water that drains from the soil.

Best with Dome: FiGoal 4 Pack Sprout Tray with Cover

Ideal Humidity Levels

Sprout seedlings without needing to worry about soil or cells with this water-only seedling starter tray

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Why It Made the Cut: Control the humidity level inside each of these four seedling starter trays using the included humidity domes.

Specs: 

  • Capacity: Variable based on plant type
  • Material: Reusable plastic
  • Dimensions: 10 x 12.5 inches

Pros:

  • Four seedling starter trays with humidity domes
  • Reusable for multiple home grows
  • Uses seedling paper instead of soil

Cons:

  • Does not come with seedling paper

In contrast to other seedling starter trays, these FiGoal Sprout Trays do not require soil pods to help seeds germinate and sprout. Instead, the seeds can be placed directly into the tray and covered with seedling paper to help provide stability for the roots. These seedling starter trays consist of a base tray, a watering mat, and a humidity dome. The watering mat sits inside the base tray and the seeds should be spread out across the bottom of the watering mat. Then, lay a piece of seedling paper over the seeds. The seeds will absorb water as necessary and sprout through the seedling paper. However, it should be noted that this set of four seedling starter trays does not come with seedling paper.

Each tray is made of reusable plastic and measures 10 inches by 12.5 inches. Because of the method used for germinating and sprouting seeds, the capacity of these trays varies with the plant type. Some plants will require more space to properly sprout than other plants, so it is difficult to estimate the total capacity.

Best with Watering Mat: Burpee Seed Starter Tray

Automatic Watering

Don’t worry about watering on a precise schedule when this seedling starter tray allows the plants to draw water as necessary.

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Why It Made the Cut: The base tray and watering mat hold excess water until it’s needed for germination, sprouting, and growth.

Specs: 

  • Capacity: 32 extra-large cells
  • Material: Reusable plastic and thin, disposable plastic
  • Dimensions: 10 x 20 inches

Pros:

  • Comes with a watering mat for automatic watering
  • Extra-large cells for strong root systems
  • Includes natural coconut fiber growing plugs

Cons:

  • Cell trays are made with thin, disposable plastic

While most seedling starter trays can include standard-sized cell trays, this Burpee Seed Starter Tray has two cell trays that each have 16 extra-large cells, making them ideal for plants with strong, deep root growth. The cell trays have drainage holes in the bottom and can both sit within the 10- by 20-inch base tray, which doubles as a watering mat, allowing the seeds and seedlings to absorb water from the tray as necessary instead of oversaturating the soil.

This product also comes with 32 natural coconut fiber growing plugs, so users can get started on their next home grow as soon as they have the seeds for the coconut fiber growing medium. Use the included humidity dome to help accelerate germination, but keep in mind that while the base tray and dome are made with reusable plastic, the cell trays are thin and disposable, so they may need to be replaced after two or more home grows. 

Things to Consider Before Buying Seedling Starter Trays

Don’t settle for just any seedling starter tray when the wrong product can reduce your chances for successful germination and transplantation. Instead, take some time to learn about the various product factors that can influence product quality in order to find the best seedling starter trays for your home.

Tray Capacity

The capacity of a seedling starter tray can range significantly from a single cell tray that can manage three to four seedlings, to seedling trays with more than 40 cells. Consider the number of plants that you want to grow, the space necessary for these plants to properly germinate, and the space required for the seedlings to finish growing after being transplanted into individual pots or a garden. 

Keep in mind that some plants will also require larger cells because they tend to sprout dense roots that need more space to grow and expand. Before starting any gardening project, research the individual plant species to determine the specific needs of the plant. This foundation of knowledge will make it easier to decide on the best seedling starter tray capacity.

Material

At first thought, the material for a seedling starter tray seems like a trivial matter. After all, the tray is just used to hold the seedlings while they grow. However, these trays can be made of thick, reusable plastic; thin, disposable plastic; and even biodegradable peat pots that are specifically designed for planting directly into the garden without having to remove the seedlings.

Biodegradable trays are a popular option for people that have a hard time properly transplanting their seedlings, but these products rarely have the same capacity as plastic seedling starter trays. Choose a thick, reusable plastic starter tray if you are planning on regularly growing seedlings at home, but keep in mind that the tough plastic makes it more difficult to take the soil plug out of the tray cell during transplantation. On the other hand, it’s easier to remove the plugs from thin plastic starter tray cells, but these disposable products won’t typically last for more than one or two home grows. 

Extra Features

Despite the simplicity of seedling starter trays, they can actually come with several different added features that manufacturers have included to improve the product. These include a humidity dome, a base tray, a watering mat, and a heating mat. 

  • Humidity domes are essentially clear plastic domes that are intended to cover the seeds and soil plugs to help maintain an ideal humidity level during the germination period.
  • Base trays are commonly used to catch excess water from the seedling starter tray cells, reducing the chance of mold, mildew, and disease.
  • Watering mats help to make the growing process easier. These mats are filled with water and sit underneath the seedling cells, allowing the plants to draw water from the mat at any point without oversaturing the soil. This is a basic form of hydroponics.
  • Heating mats are rarely included with seedling starter tray sets, but they are a good accessory to help increase germination and growth rates.  

FAQs

Q: Are seedling trays reusable?

Whether the tray can be reused or not depends on the specific product. Some trays are made with thin plastic that isn’t very useful for more than one or two seedlings germination periods, but other products are made with thick, durable plastic that can be reused multiple times. It should be mentioned that seedlings are more difficult to remove from these hard plastic trays.

Q: Do seed starting trays need drainage holes?

If you don’t want the water from the seedlings to spill out onto your counter, table, or seedling shelf, then you should have at least one base tray that does not have drainage holes. However, the pots or cells where the seedlings are grown should have drainage holes to prevent the build-up of excess water, which can lead to mold and mildew growth and damage the seedlings.

Q: How long can seedlings stay in trays?

Seedlings typically outgrow their starter trays within about three to four weeks. If the seedlings are not removed before they outgrow the tray this can lead to the plants becoming root-bound. This means that the roots have twisted and turned, growing into a tangled mass that inhibits further growth.

Q: How long do you keep seedlings in the humidity dome?

A humidity dome is specifically intended to trap humidity and moisture, making it easy for the seedlings to germinate, but as soon as you see the plants poking out through the top of the soil it’s time to remove the humidity dome. Leaving this dome on for a longer period of time keeps the seedlings trapped in an overly humid environment, which can lead to mold, mildew, and disease.

Final Thoughts

Equipped with a grow light and a humidity dome the Super Sprouter Deluxe Propagation Kit is an excellent option, but if you need a product with a greater seedling capacity, go with the affordable VpnDiyp 180 Cells Seed Starter Tray.

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