The Best Seed Starting Trays For Beginner Gardeners

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Seed starting trays are one of the easiest ways to start vegetable, flower, and other plant seedlings indoors before the weather warms up. They come in a variety of sizes, with different features, and materials, but which ones are best?

Are some seed starting trays better then others and why? This is what I set out to find out this years growing season, in my quest to grow more of my own vegetables at home!

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Are Seed Starting Trays Absolutly Necessary?

In past years, I never really used seed starting trays and always went with a collection of mixed solo cups, old flower pots , yogurt containers, egg cartons, basically whatever I could find and put soil in! While all these containers do work, and can be a great way to garden on a budget, I never really found that much success with my mix and match approach.

The main problem with this approach is that it simply makes things harder to manage. The various containers all require different amounts of water to stay moist, they take up way more space, and you have to move each seedling individually should you want to move them out, under grow lights or into a new window sill.

In short, are seed starter trays necessary for the beginner gardener? No, not exactly, but they sure do make life a whole lot easier, and dramatically improve your chances of success!

Why would we recommend using seed starting trays?

Seed starter trays make life a whole lot easier by conveniently grouping seedlings into easy to manage trays.

• It is much easier to provide adequate lighting when all the seedlings are grouped closely together instead of being spaced out in various size containers. The trays easily fit under grow lights, and can easily be moved around as a group.
• As the seed tray cells are all a uniform size, it is much easier to water, and stay on top of the moistures requirements of the various seedlings. As the seed trays all contain proper drainage, they also help prevent over watering the seedlings.
• It is much easier to plant similar types of plants in their own trays, for example herbs in one, lettuces in another, etc. This helps when needing to harden off or transplant certain seedlings before others.
• Some seed trays even come with clear plastic covers or domes, which help regulate moisture, especially in the beginning phases of germination and growth.

Different Seed Starting Tray Materials and Designs

Most often seed starting trays are made of rigid plastic and are reusable, or are made of super thin recyclable plastic that is meant to be thrown away after using. Some are a combo of plastic drip tray with bio-degradable cells or peat pellets that can later be planted right into the garden.

There are a wide range of designs to choose from, and it can be overwhelming, especially for new gardeners.

Which you'll end up choosing depends on several factors and we'll go over some of the most common designs in this guide to help you decide what will work best for you.

Seed Tray Sizes

Most seed starter trays come in a 10" x 20" size, but differ in the amount of 'cells' or individual plants that can be planted in the tray.

The more cells a tray has, the shorter the time frame before the seedlings out grow the tray and need to be planted out or transplanted into larger containers.

Tray sizes range from 12 cell trays - 128 cell trays! In my experience, tray sizes between 24 cells and 48 cells work best and will safely keep your plants indoors for 4 to 8 weeks before needing to be transplanted.

• Trays with a high number of cells (and thus a shorter growth time indoors) work especially well for lettuces such as spinach, kale, and head lettuces, which can be transplanted out into the garden sooner, either under hoop tunnels or in cold frames, then other plants.
• Trays with a smaller number of cells (for example 24 - 36 cells per tray) are ideal for plants such as tomatoes, cucumbers, bell peppers, herbs, and squashes.

Root vegetables, should when possible always be planted directly in the garden and not transplanted.

If you see roots coming out of the cells or peat pellet inserts, it's time to transplant the seedlings into a larger container or into the garden.

Bio-degradable inserts vs plastic cell trays

Which style of seed starter tray you choose is ultimately up to you.

Bio-degradable cell inserts are great, and make transplanting easy as the entire 'cell' is simply transplanted directly into a larger container or into the garden, and the tray material bio-degrades. They do need to be replaced yearly though and have a tendency to develop mold easier then plastic cell trays do.

Plastic seed starter trays are mostly re-usable, especially the more rigid plastic celled trays. The seedlings can be slightly harder to remove from the trays at transplanting time though, and you may need to use a butter knife, or spoon handle to help loosens the sides of the individual cells.

Never pull on the seedling stems to try and remove the cell from the tray as you will most probably damage the plant!

Additional accessories for your seed trays

Consider these accessories when starting and growing seedlings indoors. They make life a whole lot easier, and increase your chances of success! If you have to pick just one of them, I will always recommend grow lights be the first upgrade to your indoor seedlings!

• LED Grow Lights- specially designed lights to provide the proper amount of lights seedlings require to prevent growth issues.
• Heat Mats- help by keeping soil temperatures consistently warm, speeding up and aiding in germination rates.
• Base Trays- provide drainage for trays with drainage holes, and allow you to water your seedlings from below. Tis can help prevent disease and pest problems!
• Clear Dome Lid- Help keep heat and moisture in the seed tray. Especially important when waiting for seeds to germinate. A great and cheap investment when heat mats are not possible.

The Best Seed Starting Trays For Beginner Gardeners

In our quest to discover which seed trays work best for our vegetable garden needs, we purchased and trialed three of the most commonly available styles of seed starting trays. Biodegradable cell inserts on a plastic base tray, peat pellet inserts with a base tray, and a rigid plastic celled tray with a base for watering.

Jiffy Professional Greenhouse 72-Cell Starter kit

Review:

A great seed starting tray for beginners, just add water and the peat pellets expand. No need for extra potting soil, or filling pots. Seeds sprout quickly and the clear heat dome helps retain moisture, reducing the need to water as often. Downside to this size tray is the short growing time before the seedlings need to be moved to larger pots or transplanted into the garden. Plan accordingly. Perfect for lettuces or plants that can be transplanted within a week or two of germination.

Pros:

• Easy to plant peat pellets
• Comes with clear lid to retain moisture
• Comes with base tray for easy watering
• No need to purchase potting soil

Cons:

• Seedlings quickly outgrow the peat pellets
• pellets need to be replaced after each use

32 Cell Peat Pot Strips

Review:

Large peat pots provide enough space for plants to grow for 6 to 8 weeks. Perfect for tomatoes, peppers, cucumber, or squash seedlings. Base tray allows for easy watering, though care must be taken not to overwater to prevent mold growth. We found cutting the strips apart before planting made transplanting easier, with less disturbance to the plants. A great, easy to use tray for most plants.

Pros:

• Bio-degradable inserts make planting and transplanting easy
• Larger cell size allows for seedlings to stay indoors longer nd develop healthy root systems
• Comes with base tray for easy watering
• Allows for longer growth time before transplanting

Cons:

• Inserts need to be replaced yearly
• Requires a solid watering tray (sold separately)
• Requires potting soil to fill.

Re-Useable 72 Cell Plug Tray

Review:

The re-useable nature of this seed tray requires only adding new potting soil before each use. The deep 1.8 inch plugs allow for more root development despite the high cell count. We found the seedlings to easily grow for up to 4-6 weeks before requiring transplanting. Perfect for herbs, peppers, lettuces etc. Plugs are harder to remove at transplant time though and require loosening of the sides with a spoon or popsicle stick, increasing the chances of damaging roots.

Pros:

• Entire plastic tray is reusable
• Each cell has dedicated drainage hole
• Deep 1.8" cells allow for more root development.

Cons:

• requires base tray for drainage
• seedlings are harder to remove then with bio-degradable inserts or pellets

Summary

Over all we found that all three styles of seed starting trays had their own pros and cons making them great for different things. With all trays we tried, we found planting 2-3 seeds per cell and then trimming back to just one seedling after sprouting to give the best results.

The small Jiffy peat plugs where great for starting lettuces, herbs, and brassicas that can be transplanted out sooner even in cool weather. Tomatoes and cucumbers struggled in these peat plugs due to the limited growing space for the roots and required transplanting into larger pots fairly quickly.

The larger 32 peat pots where wonderful for plants that require more time to establish before being planted out. Tomatoes, cucumbers, herbs, and squashes all did well in this tray for up to 8 weeks. The only downside was the need to separate and space out some of the plants once they grew so large they where shading the other seedlings.

The re-useable 72 cell tray with 2 inch plugs worked surprisingly well, even for our larger plants, such as tomatoes and peppers. The deeper cell plugs allowed the plants to stay in the trays longer then expected. Removing the plugs without damaging the roots was a bit of a challenge though and took some getting the hang of.

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Seed trays are essential for starting seeds and cuttings. Seed trays are commoly lightweight plastic, biodegrable paper, or compressed peat trays divided into separate cells, like a muffin tin, for growing individual seedlings.

Seed tray cells are usually 2 to 3 inches deep and up to 3 inches square or round. Some seed tray cells can be as small as 1 inch deep and 1 inch in diameter. Seed trays vary in size from small six packs (approximatley 4 by 8 inches) to as large as 12 by 20 inches or larger. Some seed trays come with a flat tray underneath to catch excess water. Some come with a plastic top or dome to create a small greenhouse.

There are many options available in the market. It can be overwhelming to know which one is the best fit for your needs. Here is a guide to seed trays and how they are used.

Want more information on Multi-cell seedling trays? Feel free to contact us.

Types of seed starting trays

Choose a seed tray that suits your specific needs. There are various types available, including individual cell trays, multi-cell trays, and open flat trays. Individual cell trays are ideal for larger seeds or plants that require ample space, as each cell provides enough room for seedlings to develop. Multi-cell trays are perfect for smaller seeds or plants that can be closely spaced, as they provide multiple compartments in which to sow your seeds. Open flat trays, on the other hand, are versatile and can accommodate seeds of various sizes, allowing for greater flexibility.

Plastic sectioned starting tray

Lightweight plastic tray divided into separate cells usually 2 to 3 inches deep and up to 3 inches square or round. Plastic trays can be very thin and light or heavier. Some have flexible bottoms that allow rooted seedlings to be pushed out of the tray from the bottom.

Sectioned fiber seed tray

Compressed paper fiber or peat trays are similar in size and depth to plastic trays. Sometimes sold with plastic trays that they fit beneath the setioned tray to catch water that drips through. Some are designed especially to fit onto windowsills, called windowsill sets.

Open trays or flats

Open trays or flats do not have individual cells. Flats are often 6 to 12 inches wide and 12 to 24 inches long. They can be used for starting very small seeds that can be broadcast or scattered across the the starting medium surface. Seedlings grown in open trays or flats often need thinning so that individual seedlings can grow on without competion from neighboring seedlings.

Self-watering seed trays

Self-watering seed trays have drainage holes and capillary matting. An outer tray without drainable holes fit into the bottom of the starting tray. The seedlings are watered indirectly – water put in the bottom tray is pulled up into the starting tray.

Seed trays with plastic covers

Seed trays with clear plastic covers provide extra climate control at the germianitng stage. The plastic cover or dome fits over the top of the starting tray. The plainest version of this starting tray looks something like a casserole dish. Some have high domes that allow seedlings to grow to 3 or 4 inches tall. Seed trays with clear plastic lids act as mini-greenhouses, creating a moist and warm environment ideal for germination. Others have adjustable vents that allow for temperature and humidity control. These features can be particularly useful if you are starting seeds in colder climates and want to extend your growing season.

Seed tray use tips

• Sow two or three seeds in each compartment to compensate for poor germination. If more than one seed germinates, thin out the weakest, leaving only one seedling in each section.
• All seedlings in each tray should have the same watering requirements and planting times for ease of maintenance.
• The growing medium should be premoistened before sowing seed.
• Fiber or peat trays can be cut apart and completely buried in the garden (where the material will disintegrate nautrally). Trim off any part of the pot above soil line.

Seed tray material

Seed trays are commonly made of plastic or biodegradable materials. Plastic trays are durable, lightweight, and easy to clean, making them a popular choice among gardeners. Biodegradable trays, made from materials such as peat or coconut fiber, are environmentally friendly options that can be directly planted into the ground, preventing the disturbance of young plants during transplantation.

Plastic trays

Plastic trays are the most common choice due to their durability and affordability. They are lightweight, easy to clean, and provide good insulation for young plants. Plastic trays come in various sizes and designs. Plastic trays have excellent moisture retention, helping to create optimal conditions for seed germination. However, it is important to ensure that the plastic used is BPA-free to avoid any potential harm to your plants.

Some plastic trays are made from recycled materials such as recycled plastic or compostable materials; these are an excellent choice for reducing waste. Recycled trays often have the same benefits as traditional plastic trays, including durability and lightweight construction.

Biodegradable fiber or paper trays

Biodegradable trays made from materials like recycled paper, peat, or coconut coir are an eco-friendly alternative. These trays can be directly planted into the ground, reducing transplant shock and saving the gardener’s time and effort. Peat and fiber trays have excellent water retention capabilities and promote healthy root growth. Once seedlings are ready to be transplanted, the trays can be cut apart and the indivdual sectios can be planted directly into the ground. Peat and fiber trays can be more expensive than their plastic counterparts.

Seed tray depth

Seed trays can have cells of varying depth. Some types of plants have deeper root systems and require more space to grow, while others have shallower roots and can thrive in smaller cells. Make sure to choose a seed tray with the appropriate depth for the plants you are planning to grow.

Seed tray drainage

Seed trays must have drainage holes. Good drainage is essential for preventing waterlogging and ensuring healthy root development. Look for trays with good drainage capabilities to provide optimal conditions for your plants. Seed trays commonly have bottom drainage which allows excess water to easily escape. If water does not water easily drain away, seedling roots can become waterlogged and develop root rot. Bottom drainage allows for air circulation and prevents the build-up of harmful mold and fungus. Some seed trays feature small holes on the sides of the tray. This can provide a more controlled water supply to seeds.

Seed tray buying tips

• Seed trays come in various sizes, ranging from compact ones with just a few cells to larger ones with dozens or even hundreds of cells. Consider the space you have available and the number of plants you intend to sow before making your decision. If you have limited space or are sowing a small number of seeds, a smaller seed tray would be appropriate. On the other hand, if you have a larger garden or are planning to sow a significant number of seeds, opting for a larger tray will give your seeds more room to grow and develop.
• Ensure that the seed tray has adequate drainage holes. Proper drainage is crucial for seedling health as it prevents waterlogging, which can lead to root rot and other problems. Look for trays with sufficient drainage holes to ensure that excess water can easily escape, providing your seeds with the perfect balance of moisture.
• Sectioned trays are more expensive than the single flat often used by many professional growers. Sectioned tays are worth the extra money because they prevent root competition among seedlings as roots can devleop only within confines of each section — thus reducing transplant shock.
• Plastic trays can be reused year after year. Look for stiff, solid fabrication that will not easily break.
• Self-watering trays are easy to use and worth the extra cost if you find watering on a regular schedule difficult.
• Consider factors such as durability, moisture retention, and eco-friendliness when making your decision. By selecting the right seed tray material, you can create the ideal environment for your plants to thrive and ensure a successful gardening experience.

Seed trays we like

MIXC 10 Packs Seed Starter with Humidity Dome (120 Cells Total Tray) Growing Starting Seed Starting Trays Plant Starter and Base Mini Greenhouse Germination Kit. About $17.

RooTrimmer 3.5 inch Square Nursery Pots 60pcs, Sturdy Seed Starter Trays 5 Pcs, Seeds Starting Germination, Small Planter Nursery Propagation 5 Sets. About $29.

9GreenBox – Seedling Starter Trays, 144 Cells: (24 Trays; 6-Cells Per Tray), Plus 5 Plant Labels. About $8.

RooTrimmer 54 Cell Seed Starter Trays – Sturdy and Deep Design, Perfect for Hydroponic Planting and Seed Starting (5-Pack). About $30.

Mr. Pen- Plastic Growing Trays, 5 Pack, Black, Seed Tray, Propagation Tray, Plant Trays for Seedlings, Planting Trays, Microgreens Trays, Seedling Starter Trays. About $15.

MIXC Seedling Trays Seed Starter Tray, 5-Pack Mini Propagator Plant Grow Kit Greenhouse with Humidity Vented Domes and Base for Seeds’ Starting (40 Cells Per Tray, Total 200 Cells). About $17.

Seed Starter Tray, 24 Cells Indoor Seed Starter Kit, Flexible Silicone Designed Seedling Starter Trays, Germination Tray with Humidity Dome & Lids(4in Height), Reusable & Dishwasher Safe, BPA-Free. About $17.

Jucoan 40 Pack Peat Pots Seed Starter Trays, 480 Cells Germination Seedling Pots, Organic Biodegradable Plant Germination Tray. About $20.

GROWNEER 120 Cells Peat Pots Seed Starter Trays, 12 Packs Biodegradable Seedling Pots Germination Trays. About $12.

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