WHAT PROPAGATION TRAY IS BEST FOR YOU?
For more information, please visit 24 cell seed propagation tray.
The best size cell plug seed trays for you to choose will be dependent on a few factors. We will go over the different options to help you select the best for you. Consider first, what is your intent in seed starting?
What size cell tray should I use?
Quickly review some of these seed starting questions.Are you growing a large number of one variety of plants for transplanting row crops?
Are you planting smaller numbers of a wide variety of plants?
Will you be planting your crops all at once, or will you be using the succession planting method?
What type of seeds will you be planting? Peppers, tomatoes, lettuce, watermelon, etc.?
How large are the seeds?
How long will your seedlings need to stay in the cell trays?
Will you be potting up your plant starts or planting out directly from the plug trays?
How much protected growing space do you have to start seeds in?
Will you use a heat mat or rely on ambient temperatures for germination?
Quickly review some of these seed starting questions.
Check out How to Size and Use Cell Insert Propagation Trays video for a look at how these trays are commonly used.
What size cell seed trays should I use for a Home Garden?
4 Cell Seed Starting Trays
Our brand new larger 4-cell plug inserts are deeper for growing varieties of crops that need a little more room. Eight of these removable inserts fit in a Bootstrap Farmer .
6 Cell Seed Starting Trays
Our 6 cell trays have large 5/8 inch drainage holes on the bottom making it easy to remove your plant starts. They also make use of air pruning technology with long vertical slits on all 4 sides to prevent root circling in your seedlings. For easy color coding and tracking or your starts we are super excited to also offer our 6-cell trays in 5 cheerful colors. These are great for gardeners who will be starting a small amount of lots of different varieties as you can remove each type as it is ready without disturbing all the other starts that are sharing its heavy-duty deep tray bottom watering tray. 12 fit in each tray or 6 to a tray.
Shop Bundles & Kits here.
32 Cell Seed Starting Trays
The 32 cell plug propagation tray inserts are the largest cell seed starting tray size that Bootstrap Farmer carries., measuring 2" x 2". The larger size makes them perfect for canopy development of crops.
These cell seed tray inserts can be used in two ways. Directly plant into these cell inserts with deep drainage holes with Rockwool cubes, soilless media, or soil mediums. The entire tray can be bottom watered using a shallow tray with no holes.
Another way these insert trays are used is as a holder for these seed-starting pots. Seamlessly designed to sit in a shallow tray with no holes, the insert will hold 32 of these 2.5" pots, keeping them from tipping over in a trays and making quick work of transporting them out to the garden space. The individual seed cup style is very popular for school and community projects as these can go from seed to transplant without needing up-potting in between and come in bright colors and now in clear!
Recommended Plants: Tomatoes, Melons, Cucumbers, Pumpkins, Squash, Peppers and other large-seeded crops
50 Cell Seed Starter Trays
These 50 cell propagation trays are a happy medium of saving you space in your seed starting area while still being able to plant a large number of seedlings like lettuce that will be directly transplanted. Because the 50 cell tray has a much larger soil volume than the 72 cell plug trays or 128 cell trays, you will have a bit more wiggle room when you need to transplant for optimal root growth. Plants grown in these trays will be less likely to become root-bound if unsettled Spring weather delays your planting. This size also allows for canopy development of the seedling.
If you know that your seedlings will need to be potted up before they are ready to move outside, you will want to select one of the cell trays listed below or plan on potting up into larger pots like our new 5 inch grow pots with carrier.
Plastic trays of this size are great for planting early greens and brassica crops like broccoli and collard greens for the home garden. Just be sure that if you choose to mix varieties in one cell tray, they all have similar germination times and time to transplant.
Recommended Plants: Lettuce, brassicas, cucumbers, slow-growing flowers, and herbs.
The Best Cell Plug Tray Size for Large Scale Market Gardens
72 Cell Plug Seedling Trays & 72 Cell Air Prune Trays
The 72 Cell trays are the most popular choice amongst market gardeners. They are a good balance between space for growing and seedlings per tray. Each cell is 1.5" square and 2.25" deep, making them an excellent option for a large variety of plants. These plastic trays are also a good choice for vine plants. However, you will want to transplant the vine plants earlier than you would with the 32 Cell trays to prevent root bound seedlings. This cell plug tray is designed to use a heavy-duty deep tray for easy bottom-watering.
For optimal air pruning and extremely happy plants, we recommend our 72 air prune trays. All the benefits of soil blocking without the mess!
Recommended Plants: Sunflowers, Early Season Peppers, Early Season Vine Crops, Early Season Cole Crops (Cabbage, Cauliflower, Collards, Kale, Mustard, Kohlrabi, Broccoli, Brussels sprout, Watercress)
128 CELL TRAYS
These 128 Cell Trays are a great choice if you wish to start row crops or many baby greens. This configuration is ideal for starting many seeds but is not meant for crops that need more than a few weeks. Each cell is 1" square and 2.25" deep. You will be able to plant 78% more seedlings with one tray than the more common 72 cell seed starter trays. These 128 seed trays are compatible with the heavy-duty deep tray for bottom watering. You will want to up-pot your seedlings from this size seed tray into a larger pot or grow bag if you do not plan to transplant outdoors for an extended period to prevent seedlings from becoming root-bound.
Recommended Plants: Lettuce, Herbs, Cole Crops (Cabbage, Cauliflower, Collards, Kale, Mustard, Kohlrabi, Broccoli, Brussels sprout, Watercress), Celery, Leeks, Flowers.
200 CELL TRAYS
These 200 Cell Trays are excellent trays if you want to be economical about growing cole crops, lettuces, and other small-seeded crops. You will be able to grow ~2.8 times as many plants with one tray as you would with a 72 cell tray. Each cell is 0.75" square and 2.25" deep.
If you are using a 200 cell plastic trays to start seeds, you will need to transplant your seedlings at an earlier stage. Typically once they have one, at most two sets of true leaves. This plastic tray size is most frequently used by larger-scale farmers and those who intend to pot up their seedlings multiple times before moving outside. They can also be used to start plants going into hydroponic systems if you use a soilless media like coco coir or ProMix.
Recommended Plants: Lettuce and Brassica Crops (Cabbage, Cauliflower, Collards, Kale, Mustard, Kohlrabi, Broccoli, Brussels sprouts, Watercress), Small seeded flowers.
Common Questions About Planting in Cell Trays
Can I plant root crops in plug trays?
While some experienced farmers have successfully planted crops like beets and turnips in cell seed trays, it is not recommended unless your climate does not allow for the direct seeding of root crops. Carrots, parsnips, turnips, and beets rely heavily on their taproot. This long central root is responsible for much of the water uptake of these plants, and if the root is disturbed or damaged during the transplanting process, the plant will not thrive.
Can onions and leeks be planted in seed starting trays?
If you want to learn more, please visit our website Perforated seed starting trays.
Yes, unlike other root crops, members of the allium family have congregate root structures. This means that they are much more tolerant of root disturbances during transplanting. It is common for growers to plant multiple small seeds per cell and tease them apart for later transplanting.
What are the advantages to starting seeds in cell trays vs. larger pots?
Starting seeds in cell trays, especially in the larger ones, gives the grower the advantage of being able to start more seedlings in their growing space. This is especially handy for row crops where the grower may want to plant 100 or more of each variety. Growing this many seedling starts in larger seed pots would take up way too much space. The other advantage is that you will waste less growing media starting out your seeds and then up-potting the successfully germinated starts into new pots.
Can you overwater seedlings in cell seed trays?
Yes. It is possible to overwater seedlings growing in cell trays. A common mistake growers make is to leave water in the bottom tray at all times. This will eliminate your seedling&#;s ability to get oxygen. Bottom-watering with a can be properly done by adding just enough water to allow the cell tray to evenly absorb it during the watering and no more. You want to discard the excess water as it will become stagnant and invite anaerobic bacteria to wreak havoc on your newly established seedlings.
Related: Easiest Way to Water Seedlings
How long can my plants stay in the cell tray?
Most seedlings can stay in cell trays for at least 4 weeks. The larger the cell volume, the longer a plant can grow before it becomes root-bound. Plants grown in a 200 cell tray will typically need to be potted up or transplanted outside once they have a full set of true leaves. Plants grown in a 32-cell insert pot can be kept in protected conditions for 6-8 weeks. Check out our 3.3" seed starting pots and 5" pots for up-potting starts or shop our seed starting bundles.
Why are my transplants not growing?
If your seedlings have been in the plug tray for too long, they may become root-bound. If this happens, you will see a large number of roots circling the plug when you pull it out of the tray. Plants that have become root bound do not produce new roots easily and will often stay stunted.
Transplant shock can also cause your garden plants to be stunted and remain small throughout the growing season. For more on how to avoid transplant shock, check out our Seed Starting 101 Guide for advice on how to harden off your transplants.
Can I fix a root-bound seedling or plant?
If your seedlings become root bound before you have time to plant them, you can improve their chances with a bit of extra work at planting time. Once you have the plug removed from the cell tray, gently tap the bottom of the roots to loosen the soil and use your fingers to tease them apart. It is ok and even desirable to tear a few of the roots when you do this. Separating and tearing the roots will encourage the transplant to produce new side roots and prevent further root circling.
Be sure to share your seed starting successes with us on Instagram and tag us with questions you have about the process.
Regardless of your age or experience level, there&#;s never a wrong time to try out home gardening. Whether you&#;re interested in gardening as a hobby, a side hustle or simply want beautiful blooms in your space, you&#;ll need to learn the basics. In addition to durable gardening shears, raised garden beds and other gardening supplies, an easy-to-use seed starting tray is a great way to jumpstart your journey.
SKIP AHEAD What is a seed starting tray? | How we picked the best seed starting trays | The best seed starting trays | How to shop for seed starting trays
To help you choose the best seed starting trays, we consulted gardening experts for shopping advice and compiled a list of their recommendations &#; bestselling brands like Gardener&#;s Supply and Burpee are included.
Seed starting trays are shallow trays with multiple small plots (called cells) organized in a grid, which help to germinate seeds for gardeners of all skill levels. Trays are typically made from plastic, biodegradable or compostable material, the latter of which can be planted directly into the ground. &#;[A seed starting tray] differs from planters or pots in that the space for the seed and eventual plant to grow is much smaller,&#; says Carmen DeVito, a professional garden designer and the founder of Garden Cult.
Some people use seed starting trays as a starting point for sprouting seedlings &#; &#;They are essentially temporary homes for your seedlings to grow until they are ready to go out into the garden or into their permanent homes in containers,&#; says DeVito. Seed starting trays also have drainage holes to prevent overwatering.
We spoke with DeVito and horticulturalist Nathan Heinrich, both of whom emphasized the following factors when recommending the best seed starting trays:
Material: Seed starting trays are available in either plastic or some sort of composted material, such as peat, wood pulp and coir (coconut fibers). Seed trays made from peat, for example, are beneficial because you can plant them directly into native soil once the seeds have germinated and sprouted. That said, trays made from composted material are sometimes not as durable as plastic options. Plastic seed trays are prized because they hold up well against root growth and different elements that may disturb the plant. If you do use plastic trays to grow edible plants, look for ones that are BPA free.
Soil type: Soil is foundational to plant growth, and different types may be better suited for certain types of plants. You can buy a seed starting mix that&#;s premade or you can make your own using a mix of soil and fertilizer.
Light exposure: Plants sown in seed starting trays should be placed wherever they can get sufficient light exposure. If using artificial light, however, make sure those plants are easy to grow under such conditions, according to DeVito. &#;I recommend using [seed starting trays] to start plants like tomatoes, peppers, eggplants, zucchini and some flowering perennials that do best when they are started indoors under lights,&#; she says. &#;This gives them a head start for the season to flower or produce fruit and other edible parts quicker.&#; You can also buy seed starting trays with grow light attachments if your access to natural light is limited.
Watering: Seedlings also need sufficient water to grow. In addition to watering cans, you can often buy watering trays, sometimes called a reservoir, bottom tray or propagation tray, which goes under the cells of the seed starting tray. Depending on what you&#;re planting, you can water seedlings in seed trays by either watering them from above or by adding water to the tray below. Since seed starting trays have small holes on the bottom, it allows the plants to absorb water from below. Ensuring you have the space, supplies and time to do this regularly is important if you plan on using a seed starting tray.
Below, we rounded up seed starting trays recommended by our experts and ones that have at least a 4-star average rating from at least 500 reviews on Amazon. All of them are either made of plastic, silicone or biodegradable material.
This plastic seed starting tray from Gardener&#;s Supply Company comes recommended by DeVito, who says it&#;s a great option for beginners. The seed-starting kit has two 24-cell seed starting trays with a propagation tray for watering, two germination dome covers which regulate temperature, a six-quart bag of seed starting soil mix, a capillary mat and wooden seedling marking sticks. While the seed starting tray is suitable for both indoor and outdoor gardening, it&#;s best if used for growing indoor or greenhouse seedlings, according to the brand. The propagation tray underneath the seed tray helps maintain water over time, so your plants receive continuous self-watering, according to the brand.
This biodegradable seed starting tray, also from Gardener&#;s Supply Company, comes recommended by DeVito, who says it&#;s good for gardeners who want an eco-friendly option. As is common with biodegradable seed starting trays, you can plant these pots directly into the ground due to the organic material. The wood fiber cells are both durable enough to help promote plant growth for seedlings but they&#;re also easy to work with when transplanting them into your garden bed.
This vibrant, modern-looking silicone seed starting tray from Burpee is a perfect option for gardeners with limited space, like a windowsill, according to DeVito. The tray has the same features of a typical plastic or biodegradable tray, such as small holes underneath for soaking up and draining water. The most unique aspect, however, is the pliable silicone bottoms that allow you to easily press the seedlings out of the cells and transplant into native soil or a large pot when ready.
This Mixc seed starting tray has everything growers want to sow multiple types of seeds. The plastic tray kit includes a cell tray and a propagation tray, both of which fit together underneath a plastic humidity dome, also included. The dome cover also has adjustable vents on the top that you can change by hand, depending on the weather or climate you want to expose your plants to. The tray is also safe to use with a heat mat, according to the brand. That means you can have even more control over the temperature around your plants, which is important if you live in a particularly cold environment. The model has a 4.4-star average rating from over 8,000 reviews on Amazon.
The Gardzen seed starting tray has all of the basics required for setting up your seedlings. The model has the usual multi-cell seed tray, draining holes on the bottoms and a plastic humidity dome for temperature regulation. Since the brand offers large capacity cell trays, with both 40-cell and 70-cell options, each of the tray kits have domes with multiple adjustable vents on the top for optimal temperature regulation. It also has a 4.6-star average rating from over 6,000 reviews on Amazon.
The Growneer seed trays are made from peat, a biodegradable material made of composted organic material, which makes them ideal for planting the seedlings directly into the ground once they sprout. The brand sells 10-cell and six-cell trays, both of which come with T-shaped plant labels that you can stick into each cell with soil. A benefit of peat seed starting trays like this one, is that you can cut and separate each cell however you want.
If you plan on using your seed starting tray indoors, consider purchasing one with a grow light. While many plants and seedlings thrive while growing indoors, a grow light can help make the germination process smoother and faster. A grow light also makes it easier to provide your plants with light, regardless of where in your home they are, especially a space with limited natural light. The light on this tray has adjustable settings that can be controlled with a remote. Plus, it has a 4.3-star average rating from over 3,000 reviews on Amazon.
If it&#;s your first time shopping for seed starting trays, it&#;s important to keep certain features in mind, such as the material of the tray, the size and number of cells, and where you plan on transplanting the seedlings. It&#;s also crucial to make sure you have the proper space to transfer them to, such as a large flower pot or garden bed.
The type of seed starting tray you choose also matters. Seed starting trays are either made from plastic or composted material such as peat or wood fibers. Both work fine for growing seedlings, but there are benefits and drawbacks to using each type, which we explain below.
Plastic trays are a popular choice for growing seedlings because they&#;re durable enough to use multiple times. &#;The plastic [seed starting trays] are theoretically reusable and usually cheaper,&#; says DeVito. &#;[And] depending on the type of plastic, possibly recyclable.&#; That said, plastic seed starting trays are less environmentally friendly compared to peat trays since you have to remove the seedlings by hand to transplant them into garden beds or native soil.
Biodegradable trays are also commonly used for starting seeds because they don&#;t require disturbing the plant roots while transplanting. Since they&#;re made from organic material, they&#;re safe to plant directly in the ground. That said, if you&#;re an experienced gardener and plant seedlings often, keep in mind that using peat trays requires buying new ones annually, which can be costly for some.
Frequently asked questions
Seed starting trays are helpful tools for beginners, but they&#;re also something that even experienced gardeners can use to grow seedlings in a safe and organized way. &#;One of the main reasons for using seed trays with individual &#;grow cells&#; is spacing,&#; says Heinrich. &#;By placing one or more seeds into a seed tray with individual &#;cells&#; or &#;plugs,&#; you allow the seeds to sprout in their own tiny space without being over-crowded and having to compete with their fellow seedings for root space, water, and sunlight.&#;
Plus, since the seedlings are divided into individual plots, they&#;re easier to transplant compared to open seedling trays because the roots of each plant are separated. &#;While some people like to sow seeds in &#;open seed trays&#; that do not have individual grow cells, this method has a much lower success rate with most varieties,&#; says Heinrich. &#;While it is a faster way to sow your seeds initially, you end up with more labor when it comes time to divide the seedlings for transplanting.&#;
Yes, seed starting trays, even ones that you make from more common biodegradable material, such as egg cartons, need drainage holes on the bottom. This is to ensure that the roots aren&#;t overwhelmed with too much watering. Also, if you have seed trays with a propagation tray, the holes on the bottom allow you to water the plants from the underneath rather than from above.
Something important to keep in mind when using a seed starting tray is that you can use them both indoors and outdoors. Since seeds starting trays are meant for growing seedlings that will be transplanted later, whether or not to start them indoors depends on your preference and the type of plant. Some varieties are fine to plant indoors or outdoors, while some are more suited for one or the other.
Depending on what you&#;re planting and when you expect it to sprout, you should start seeds around six weeks before your last expected frost date, according to The Old Farmer&#;s Almanac. A frost date is the date that the last freezing cold temperature is projected to happen where you live. This helps prevent your plants from dying in the cold. You can use resources such as an Almanac, to see what the expected frost dates are for your area.
Professional gardeners look at planting zone maps, also called plant hardiness zones, to choose the optimal time to start their seeds, according to the United States Department of Agriculture. Planting zones are regions throughout the United States with their own climate profile, each of which has its own letter and number combination related to a certain type of climate. Planting zones range from 1a to 13b, with 1a being the coldest and 13b being the warmest. This helps gardeners and farmers know what is best to plant where they live and when.
At NBC Select, we work with experts who have specialized knowledge and authority based on relevant training and/or experience. We also take steps to ensure all expert advice and recommendations are made independently and without undisclosed financial conflicts of interest.
Cory Fernandez is a commerce editor at NBC Select, where he covers food, cooking, cleaning, lifestyle and wellness. He spoke with professional gardeners and horticulturalists for their insight, recommendations and guidance.
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