The Gardzen 5-Set Garden Propagator Set is our top pick because it includes domes and has enough room for 200 seeds.
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Better Homes & Gardens / Kevin Liang
You can start seeds in a lot of different containers, but trays specifically designed for starting seeds make the job much easier. They can help you control factors like humidity, air circulation, and drainage—which will likely lead to greater success and more plants to take to your outdoor garden later in the season.
“Seed starting trays are a great way to organize larger quantities of seeds, and they help growers maintain space and uniformity,” says Rachel Tan, Production Horticulturalist for the Greater Des Moines Botanical Garden. “Your choice of seed starting materials will depend on the amount of space you have and the types of plants you plan to grow.”
Some of the best seed starting trays are reusable, whereas others are designed to be planted directly into an outdoor garden with your seedlings. Seed starting trays also have different sizes of cells, which can accommodate different types of plants. Some trays are sold separately, while others come as part of a kit, which can be helpful for everyone, but especially beginning gardeners.
This set includes base trays, domes, and durable plastic seed starting trays.
The cells aren’t as big as others on our list, so you may need to transplant them early.
This seed starting tray kit will provide everything you need to easily start seeds for your garden. Five trays of 40 cells each will give you space to start 200 seedlings. Each seed starting tray comes with a base tray to catch water from the drainage holes in the seed starting tray; it also allows you to water from the bottom—either way, it will help ensure you don’t overwater your seedlings.
The trays also come with a dome to help you ensure enough humidity for proper seed germination. Since the trays are BPA-free, they are safe to use for vegetables as well as flowers. Made out of a sturdy plastic, they hold up well to being moved or reused.
Each cell in these seed starting trays measures 1.4 x 1.4 inches and is 1.85 inches deep. While these aren’t the biggest cells on the market, they will work well for most types of seeds. You will likely need to transplant them into a larger container or transplant them into the garden earlier than you would with a larger cell size to allow the roots enough room to grow as the seedlings get bigger.
Product Details: Size: 5 trays with 40 cells each | Cell Dimensions: 1.4 x 1.4 x 1.85 inches | Material: Plastic | Drainage Holes: Yes | Accessories: Base tray, dome
This set includes 720 cells that are 2.25 inches deep.
These trays are sold without any extra accessories, so if you want domes or base watering trays, you’ll have to purchase those separately.
The best seed starting trays don’t have to break the bank. The Industry Standard Grower's Supply 720-Cell Seedling Starter Trays give you a lot of space for starting seeds at an affordable price. With 120 trays of 6 cells each, you’ll have plenty of flexibility to use some now and save some for next year.
Plus, because these trays are small, you can assemble a grouping under grow lights or just start a few on a windowsill—whatever works for you and your space. The cells in each tray measure 1.5 inches square and 2.25 inches deep, so they are ideal for starting a wide variety of seeds. These trays are reusable, but there are so many trays in the pack, you may choose to just grab new trays from your collection next year, especially if you only start a few seeds each year. Drainage holes at the bottom of each cell will help ensure you don’t overwater your seedlings.
These seed starting trays don’t come with any extra accessories, so you’ll need to buy those separately if you need them. These are a great option if you already own domes and base watering trays, but if you are just trying seed starting for the first time, you might prefer an all-in-one kit that provides all the seed starting essentials you’ll need.
Product Details: Size: 120 trays with 6 cells each | Cell Dimensions: 1.5 x 1.5 x 2.25 inches | Material: Plastic | Drainage Holes: Yes | Accessories: Five plastic plant labels
Unlike many other options, there is a bit more space in between the cells to prevent any overlap as plants grow.
The dome and tray are reusable, but you’ll need to buy new planting blocks with soil plugs each year.
If you are able to splurge a bit on your gardening supplies, this mini greenhouse kit offers several key features to help you grow strong, healthy plants.
The extra space between cells in this tray’s design allows plants a little more room to spread out so they can grow to a uniform width and height. The bio sponges that come with the kit (and serve as the planting medium) improve germination rates and help encourage roots to grow downward rather than in a spiral that may end up strangling the plant. The sponges also make the seedlings easy to transplant directly into the garden, so you are less likely to need to transplant them into a bigger pot first.
The clear dome that’s included in the kit features adjustable vents, which gives you more control over humidity levels and improves air circulation. The kit also comes with a base watering tray and a packet of seedling food that can be dissolved in water in the base tray to encourage healthy plant growth.
You can use the durable and sturdy bio dome for many years, but you will need to purchase refills of the planting block (seed tray) with new bio sponges for future plantings.
Product Details: Size: 1 tray with 40 cells | Cell Dimensions: 1.375 x 1.375 x 2.5 inches | Material: Polystyrene | Drainage Holes: Yes | Accessories: Dome, 40 bio sponges, seedling food
We love that this tray is dishwasher safe—plus the flexible cells make it easy to remove seedlings without damaging the roots.
This tray doesn’t come with a dome like some other sets do, and you’ll need to purchase seed starting soil separately.
While plastic seed starting trays are all technically reusable, many of them get crinkled up or torn when you try to remove seedlings for transplanting. This silicone seed starting tray is easy to use time and time again, since it’s sturdy, flexible, and easy to clean.
The flexible cells in this tray make it easy to pop out seedlings when you’re ready to transplant them into your garden. That means you’re less likely to damage the roots as you remove them from the tray. A base watering tray is also sold with this seed starting tray.
Molded slots in the corners of each cell help water drain into the tray below, and a raised perimeter helps keep water in the tray. The cells are a generous 2 inches wide and 2 inches deep, making it a good choice for starting a variety of seeds. Rubber coated handles make it easy to move the tray if needed. We love the fact that it’s dishwasher safe, so it’s simple to get it ready for another round of seeds or for the following gardening season.
The tray is sold with a thoughtful planting diagram chart to help you keep track of what you planted in the tray. The only downside is you will need to purchase a dome and seed starting mix or pellets separately.
Product Details: Size: 1 tray with 16 cells | Cell Dimensions: 2 x 2 x 2 inches | Material: Silicone | Drainage Holes: Yes | Accessories: Watering tray, planting diagram
These trays can be planted directly into the garden with your seedlings.
Don’t overwater seedlings or these biodegradable trays might start to break down before you get a chance to plant them in your garden.
For some gardeners, the best seed starting trays are the ones you can plant directly into the ground with your seedlings. These biodegradable trays are made primarily of paper and peat moss, so they will break down in the soil over time. This means you don’t have to remove the seedlings when it’s time to plant, which helps you avoid disturbing the plants’ roots and decreases their chance of transplant shock.
This set gives you plenty of space for starting seeds, with 12 trays of 10 cells each. The cells are good size, too—1.95 inches square and 2 inches deep—ensuring that there is enough room for seedlings to grow.
Drainage holes at the bottom of each cell help you avoid overwatering. Because the trays are made of paper and peat moss, they break down quickly once planted in your garden. Unfortunately, this also means that they are prone to breaking apart before that if you overwater your seedlings.
Unlike other types of seed starting trays, these are not reusable so you’ll need to buy new trays each growing season. You’ll also need to purchase seed starting mix separately.
Product Details: Size: 12 trays with 10 cells each | Cell Dimensions: 1.95 x 1.95 x 2 inches | Material: Peat | Drainage Holes: Yes | Accessories: Plant labels, dibber, widger
This kit includes a self-watering mat that helps ensure your seedlings get just the right amount of water.
There are only 72 cells, unlike other trays that have a couple hundred or more.
For beginning gardeners, the best seed starting trays are ones that make the process easy. This kit does just that, since it comes with everything you’ll need to start seeds indoors, including a self-watering mat that helps draw up water to your plants from the base watering tray. This mat helps you ensure you give your seeds enough moisture without accidentally overwatering them.
The kit also comes with pellets of coconut coir to grow your seeds in. The pellets expand when you add water and help hold the optimal amount of moisture for your seedlings. Two plant stands and a dome are also in the kit, as well as a planting diagram to help you keep track of what you’ve planted where. There’s also a tool to help you mix up the soil after you add water to the coir pellets.
With two trays of 36 cells each, you’ll have plenty of room for starting plants indoors, and the cells are large enough to accommodate most types of seeds. Other seed trays on our list have hundreds of cells, so if you plan on planting an abundance of seeds, this may not be the best seed starting tray for you.
The trays can be reused if you are careful with them, and Burpee sells self-watering mat replacements if needed. Because this kit helps you avoid overwatering your plants (and helps retain moisture if you forget to water one morning), this is a great kit for someone starting seeds for the first time.
Product Details: Size: Two trays with 36 cells each | Cell Dimensions: 1.5 x 1.5 x 2 inches | Material: Plastic | Drainage Holes: Yes | Accessories: Dome, self-watering mat, watering tray, growing pellets, plant stands, soil mixer, plant markers, and planting diagram
The domes in this set come with vents that allow you to have better control over humidity levels and air circulation.
Pellets and seed starting mix aren’t included.
If you’re looking for a tray with a dome, the Bonviee 10 Pack Seed Starter Kit is the best seed starting tray for you. In this kit, you get 10 trays with 12 cells each—and each tray comes with its own dome. The domes come with vents to allow you to regulate humidity—in fact, you can adjust the humidity level from 50 to 100 percent.
The seed starting trays in this set are transparent, so you can observe the roots’ growth and get a better idea of when to transplant them outside (plus, we think they would be a great way to teach kids about plant growth).
At 1.5 inches square and 2 inches deep, the cells are big enough for most seeds and each has a drainage hole to make sure you don’t overwater your seedlings. The kit also comes with sturdy base watering trays that are durable enough to reuse, plant labels, and small gardening tools. You’ll need to buy pellets or seed starting mix separately.
Product Details: Size: 10 trays with 12 cells each | Cell Dimensions: 1.5 x 1.5 x 2 inches | Material: Plastic | Drainage Holes: Yes | Accessories: Domes, base trays, adjustable vents, plant labels, and small garden tools
The peat pellets accommodate plants with longer roots.
The seeds aren’t included in the kit.
For those looking for a kit, the Ferry Morse Jiffy Tomato & Vegetable Greenhouse kit is our top choice. It includes two sturdy seed starting trays with 36 peat pellets, a clear humidity dome, plant markers, and Ferry-Morse’s SuperThrive, a kelp-based plant vitamin sample to give your seedlings an extra boost.
The 1.96 inch peat pellets give the seedlings more room to develop larger roots before you transplant them into the garden. This is ideal for peppers and tomatoes that may not grow as well in smaller pellets and cells (unless you transplant them into a larger container right away).
Although some gardeners have concerns about the environmental effects of using peat, the peat pellets in these kits are sourced from Canadian Sphagnum peat moss bogs that use sustainable practices.
The pellets include a biodegradable netting that will break down in the soil so you can plant the pellet and seedling directly into your garden. And don’t be fooled by the peat pellets that look quite thin—they expand to over seven times their height when you soak them in water.
You’ll find everything you need in this kit—except for the seeds. We also like the fact that the trays in the kit are made from recycled materials. And you can reuse the kit again—you’ll just need to purchase replacement pellets or buy seed starting mix.
Product Details: Size: 2 trays with 36 cells each | Cell Dimensions: N/A (50 mm pellets) | Material: Plastic | Drainage Holes: No | Accessories: Domes, watering trays, peat pellets, SUPERthrive plant nutrient sample, and plant markers
These silicone trays are durable, easy-to-clean, and available in a variety of fun colors.
There are only 12 cells, so you’ll need to buy multiple sets if you want to start a lot of seeds—be sure to factor that into your budget.
The Sili-Seedlings Seed Starter Tray is the best seed starting tray for those looking for a reusable silicone option. This dishwasher-safe tray is made of BPA-free silicone so you can use it to start vegetable seeds without any concerns about chemicals leaching into the soil.
Because the silicone is so flexible, it’s easy to gently push out the seedlings when it’s time to transplant them into the garden without damaging the root system. In this set, you get two silicone trays with 6 cells each, and the trays are small enough to be grouped together under a grow light or placed on a windowsill.
However, since there are only 12 cells, there may not be enough for some gardeners if they’re planning to start a lot of seeds. The tray’s cells themselves are a generous size though (2 x 2 x 2.25 inches), so they’ll work well for a wide variety of plants.
We also love the fact that it's available in several different bright colors like emerald green, sapphire blue, slate gray, sunstone orange, and volcanic black. You can also write on the tray with a dry erase marker to easily keep track of what you’ve planted where—just wipe away the writing later with rubbing alcohol.
Product Details: Size: 2 trays with 6 cells each | Cell Dimensions: 2 x 2 x 2.25 inches | Material: Silicone | Drainage Holes: Yes | Accessories: None
The self-watering feature helps you avoid overwatering seedlings.
It does not come with seed starting mix or coir pellets like some other kits do.
The GrowEase Seed Starter Kit may be small, but it has a lot of advantages. This self-watering kit will help you avoid overwatering your seedlings. Additionally, the seed starting tray, base watering tray, and plant platform are all dishwasher safe so they are easy to clean between uses.
The capillary mat, which helps draw up water to the seedlings from the base tray, can be hand washed and used again, too. The kit is made from recycled plastic that is BPA-free, so you can plant any type of seeds without concern. A clear dome is also included in the kit to help control humidity.
With just 12 cells each, these seed starting trays fit easily on a windowsill if you want to start seeds there. (A 24-cell version is also available.) Although this size may not be enough to start all your seeds, the narrow trays offer more flexibility if you want to place them in different parts of the house rather than under one grow light.
We like the fact that the platform doubles as a tool to help eject seedlings when you are ready to transplant them into your garden. The cells are 2 inches square and 2.25 inches deep, giving seedlings plenty of room to grow. Keep in mind that pellets aren’t included in this purchase.
Product Details: Size: One tray with 12 cells | Cell Dimensions: 2 x 2 x 2.25 inches | Material: Recycled plastic | Drainage Holes: Yes | Accessories: Dome, water reservoir, capillary mat, and platform
This 144-cell seed starting set is made of sturdy, reusable plastic.
At 1.5 inches square, the individual cells are slightly smaller than other cells on our list.
If you have a large garden, this may be one of the best seed starting trays for you. With three trays that have 48 cells each, this seed starting kit gives you a lot of space for starting seeds. In addition to the seed starting trays, you also get clear domes, base trays, plant markers, and a few small garden tools.
The materials are made from sturdier plastic than some kits, so you can reuse them for several growing seasons. Air vents are included for the domes, so you can better control humidity levels and air circulation. Drainage holes at the bottom of the seed starting trays help avoid root rot if you accidentally overwater your seedlings.
These trays are too large for a windowsill, so they are best suited for a multi-tiered grow light rack or a greenhouse. As is common with trays that have a lot of cells, the individual cell size is somewhat small at 1.5 inches square—but they’re still big enough for a majority of seeds. You are likely to need to transplant seedlings into larger containers as they get bigger, though.
Product Details: Size: 3 trays with 48 cells each | Cell Dimensions: 1.5 x 1.5 x 2 inches | Material: Plastic | Drainage Holes: Yes | Accessories: Domes with air vents, water trays, plant labels, and small garden tools
After conducting research, we chose the Gardzen 5-Set Garden Propagator Set as the best seed starting tray because it provides abundant room for starting seeds and is sold with accessories to make starting seeds easier. If you want a seed starting tray that will be able to be reused for years to come, we recommend the Sili-Seedlings Seed Starter Tray.
The best seed starting trays are the ones that fit your space. Larger trays are often ideal for gardeners who plan to start a lot of seeds in a multi-level seed starting station with grow lights, like the Delxo Seed Starter Tray. A smaller seed starting tray, such as the Growease Seed Starter Kit, will be best for someone who wants to place the tray on a windowsill.
In addition to overall size, consider how many cells are in each tray. “Generally, the larger the number of cells on a tray, the smaller the size of each cell,” says Tan. “Small cells will often need to be transplanted into larger pots or trays, while some large-celled plugs can produce plants strong enough to be sown directly into soil in the garden.”
Many seed starting trays are made of plastic, which are generally reusable. However, the thicker the plastic, the more durable they are and the more likely they will be able to be used again. Other seed starting trays are made of silicone which are dishwasher safe and are easy to clean and use again.
Biodegradable trays, meanwhile, are designed to be used only once. Most of these are made from peat or paper and are designed to gradually break down over time. “They can be directly planted into the soil, which can reduce transplant shock,” Tan says. “Some can even provide fertilizer to your plants as they break down in the environment.”
Seedling trays are sold separately or as part of a kit that often comes with several accessories, such as a base tray so you can water from the bottom and a dome to help control humidity.
“Soil moisture is crucial for seed germination, so a humidity cover/dome is important at the very beginning,” says Lindsay Miller, horticultural writer for Gardener’s Supply Company. “Just remove it once seedlings have sprouted.”
You may also find kits that include small gardening tools and plant labels to help you keep track of what you planted in which cells.
While you don’t have to use seedling trays, they make the process of starting seeds easier. “You can certainly get creative and repurpose yogurt cups or other containers you have laying around, but there are a ton of seed starting options out there, each with big advantages over a regular cup,” Miller says.
A majority of the best seed starting trays offer drainage holes and some come with a self-watering mat that helps draw water up from a tray below. Some seed starting trays are biodegradable, so you can just put the container and the seedling into the ground and decrease the risk of transplant shock. So while you can use other items, it may be more beneficial in the long run to use a product specifically designed for starting seeds.
The material you should choose for your seed starting tray will depend on your needs and what plant you are growing. If you want to reuse a tray year after year, you’ll want to choose silicone or a heavy-duty plastic.
If you’re growing vegetables, you’ll want to choose a BPA-free plastic, but if you’re starting flower seeds, this might not be as important. You may want to opt for a biodegradable option, like the 2NLF Seed Starter Tray, if you’re growing plants that may be more likely to suffer from transplant shock, such as root crops like carrots.
The optimum depth for a seed tray will vary depending on what types of plants you are growing and how long you want to keep them in the seed starting tray before transplanting them into a bigger pot or into the ground.
You can start a variety of types of seeds indoors, including perennial flowers, annual flowers, herbs, and vegetables, and some plants have larger roots than others. “On average, aim for 2-inch-deep pots,” Miller suggests.
If you want to keep them in the seed tray until they’re ready to be transplanted outside, a deeper tray will be better. Keep in mind the specific plants that you’ll be growing and their individual needs.
“I would grow my vegetables in flats with a cell depth of about 2 inches,” Tan says. “But I would grow native prairie plants in a cell with a depth of about 6 inches to allow more space for the roots to grow.”
Renee Freemon Mulvihill is a freelance writer specializing in home and garden topics. For this article, she spent time researching seed starting trays and kits online. She also consulted Lindsay Miller, a horticultural writer for Gardener’s Supply Company, and Rachel Tan, Production Horticulturist for the Greater Des Moines Botanical Garden, to get their advice about the best seed starting trays and supplies.
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