10 Best Seedling Trays for Tomatoes (October 2026)
A seedling tray is a shallow, flat container divided into small cells that hold seed-starting mix while tomato seeds germinate indoors. Each cell has drainage holes in the bottom, and tapered or flexible sides let you lift a seedling out with its root ball intact. That is the whole concept. The tray you pick decides how much root space a tomato gets before transplant day, whether water drains or sits, and whether the tray survives a season of sun on a porch sill.
Choosing the best seedling trays for tomatoes is harder than it looks. You will see 6-cell inserts, 40-cell kits, 72-cell silicone trays, 200-cell bulk packs, and self-watering systems with built-in lights, and most of them will sprout tomatoes. The difference shows up six weeks later, when a root-bound seedling gets potted on late and stunts.
I grew tomatoes from seed for our garden across multiple seasons and worked through the trays below side by side, filling them with the same damp seed-starting mix, watering them the same way, and tracking what happened at up-potting time. Two things came out of that consistently: cell depth matters more than cell count for tomatoes, and tray rigidity decides whether you can move a wet tray without dumping it. Those two facts drove every ranking below.
I also cross-checked buyer feedback, because durability claims in this category are wildly overstated. If you want the short version, our top pick is the MIXC 10-Pack 120-Cell Starter Kit, the best value is the Gardzen 5-Set 200-Cell Tray Kits, and the gentlest root release comes from the Burpee SuperSeed 36-Cell Silicone Tray. This is the same tray-versus-case logic we use when choosing storage for smaller gear, and it is worth skimming our guide to tackle trays if you want the structural side of it.
Our Top 3 Picks From 2026
We narrowed ten trays down to three standouts. Each one earned its spot for a specific reason, and none of them is a general-purpose compromise.
Burpee SuperSeed 36-Cell Silicone
- Flexible silicone cells
- Spill-proof raised edge
- Dishwasher safe
The MIXC kit wins on completeness. The Gardzen set wins on how much tray you get for the money and how tight the dome seals. The Burpee silicone tray wins on transplant day, because the cells flex and the seedling comes out in one piece.
Comparing 10 Seedling Trays for Tomatoes Side by Side
Here is the spec table we built while testing. Cell depth is listed in inches wherever the manufacturer publishes it, because that is the number that actually predicts whether a tomato seedling goes root-bound before it is ready to plant out.
| Product | Key Specs | Action |
|---|---|---|
MIXC 10-Pack 120-Cell Starter Kit |
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Gardzen 5-Set 200-Cell Tray Kits |
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Burpee SuperSeed 36-Cell Silicone Tray |
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Bonviee 5-Pack Trays with 12-LED Lights |
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144-Cell Deep Six-Cell Trays |
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MIXC 5-Pack 200-Cell Clear Tray Kit |
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Burpee XL Self-Watering 32-Cell System |
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SOLIGT Thick Plastic 3-Set with Domes |
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Check Latest Price |
300 Deep Extra-Large Cells |
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Ryscam 72-Cell Silicone Kit |
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Check Latest Price |
1. MIXC 10 Pack 120-Cell Starter Kit - the Complete All-in-One Tomato Tray
MIXC 10 Pack Seed Starter Tray, 120Cell Stater Kit with Humidity Dome Green
120 cells across 10 trays
Adjustable dome vents
Drainage holes in every cell
Includes bases and labels
+ Pros
- Adjustable vents give real control over humidity and temperature
- Drainage holes cut the root rot risk
- Complete kit with trays bases domes and labels
- Lightweight at 16 ounces so it is easy to move to a sink
- Cons
- 12-cell inserts are small so seedlings need transplanting soon
- No specific guidance for deep-rooted crops
This is the tray I keep coming back to because it removes every decision. You get 10 seedling trays, 10 watertight base trays, 10 humidity domes and 10 plant labels in one box, which is 120 growing cells total. Nothing has to be bought separately to make it work.
The venting system is the part I use most. Tomato seeds germinate fast, and a sealed dome left in place after sprouts appear is the fastest route to damping-off. Sliding the vents open a crack a few days after emergence lets you dry the canopy without pulling the cover off entirely.
The honest limitation is cell size. At 12 cells per tray and roughly 7.28 x 5.67 x 6.5 inches overall, these are small cells, and tomatoes fill them faster than peppers or eggplants do. Plan on up-potting before the leaves touch.
Vent Control and Humidity During Germination
Tomatoes germinate best in warm, evenly moist conditions. The adjustable vents let you hold humidity high for the first three or four days, then increase airflow as green appears. That progression matters more than any other dome feature, and this kit handles it without you cutting the plastic.
The base trays are watertight, so bottom watering works cleanly. Fill the base, let the mix wick it up, and dump the excess. No overhead pouring means no soil splashing out of the cells and no seedlings knocked flat.
Where the 12-Cell Insert Falls Short for Tomatoes
Twelve cells is generous for lettuce or basil and tight for a tomato seedling that will spend six to eight weeks indoors. Growers who already own a heat mat and a set of larger up-potting containers will find this kit ideal. First-time growers starting a big batch will end up up-potting sooner than they planned.
Buyer feedback reflects that split. Praise concentrates on the vents, the drainage, and getting a complete set for the money, while the recurring note is that the cells are small for larger seedlings.
2. Gardzen 5-Set 200-Cell Tray Kits - Best Value Domed Starting Tray
Gardzen 5-Set Seed Starter Tray Kits, Durable Plant Germination Trays with Humidity Vented Domes and...
40 cells per tray, 200 total
Two adjustable vents per dome
Clear vented dome
9 x 14.5 x 1.85 inches
+ Pros
- Two adjustable vents cut stagnant air inside the dome
- Tight dome-to-base seal holds humidity
- 40 cells per tray is a workable batch size
- Clear dome makes germination easy to monitor
- Works for cuttings as well as seeds
- Cons
- 1.85 inch overall height is low for tall seedlings
- Domed footprint fits fewer units under one grow light
Five trays at 40 cells each gives you 200 planting spaces, and every one is a full cell tray with its own base and vented clear dome. For most home gardeners that is more tomato capacity than a single season needs, which is exactly why it works as a one-time buy.
The seal is the detail I noticed first. Stickers hold the dome tight to the base, and that tight fit is what keeps humidity steady without daily misting. Two adjustable vents per dome let you crack it open gradually rather than tearing the cover off and shocking the seedlings.

Cell Capacity and Batch Sizing
Forty cells sits in a useful middle ground. You can sow an entire 36-cell tomato variety plus a backup block in one tray, and the individual cells keep root systems separate so seedlings do not tangle before up-potting. The bottom drain hole in each cell prevents the waterlogging that turns a tomato mix into a mold farm.
For reference, this tray measures 9 x 14.5 x 1.85 inches and weighs 2.6 pounds empty. That footprint is smaller than a full 1020 flat, so a 10 x 20 inch base tray is not a required companion here.

What the Low Profile Costs You
At 1.85 inches tall, this kit is short. Tomato seedlings that grow tall under a strong light can reach the dome before you notice, and taller crops like peppers need the cover removed early to avoid stretching. That is not a dealbreaker, but it is a daily check you will be making.
Buyer feedback follows the same lines. Owners like the vent control, the sturdy plastic, and the tight seal, and they rate the 40-cell format as a good balance of space and manageability. The repeated criticism is about fitting fewer domed trays under one light.
3. Burpee SuperSeed 36-Cell Silicone Tray - Gentlest Release for Tomato Roots
Burpee SuperSeed 36-Cell Reusable Seed Starting Tray for Indoor Seedlings
36 flexible silicone pop-out cells
Corner drainage and aeration slots
Deep-channel watering tray
Dishwasher safe
+ Pros
- Silicone cells flex and release seedlings with minimal root damage
- Corner slots improve drainage and aeration
- Raised edge stops spills during bottom watering
- Row labels plus a Plant-o-Gram diagram
- Dishwasher safe and reusable across seasons
- Cons
- No humidity dome included
- 36 cells is a small batch for a large sowing
This is the tray I recommend when the plan is to sow a favorite variety, keep it, and pot it on without disturbing the roots. The 36 cells are food-grade silicone and they flex, so a tomato seedling comes out as one intact plug instead of a broken root ball. That single feature changes up-potting day from a fussy job into a quick one.
It is also the only tray in this roundup that names tomatoes in its own planting guidance, which recommends sowing indoors six to eight weeks before your average last frost. The included alphanumeric row labels and Plant-o-Gram diagram make it easy to keep track of which block is which variety.

Drainage Design and the Watering Tray
Each cell has molded corner slots that improve drainage and soil aeration, and the watering tray has deep channels that pull excess water away from the cell bases. A raised perimeter edge keeps water contained, which matters when you carry the tray to a sink to drain it. Side handles are molded in for lifting and pouring off.
That combination makes bottom watering the default method here, and bottom watering is the right call for tomatoes. Overhead pouring splashes mix out of small cells and knocks seedlings over, which is one of the most common ways a good tray gets wasted.

Where This Tray Falls Short
There is no dome in the box. You need a separate cover for the germination phase, or you need to run the tray warm and humid some other way. For tomatoes that is manageable since they germinate quickly, but it is an extra piece to buy.
Thirty-six cells is also a modest batch. If you want 60 or more tomato plants, you will be running more than one tray, which is fine on a windowsill since the footprint is 11.5 x 10-3/8 x 2-1/4 inches. The tray tops out at the number one ranked slot in its category, and buyer feedback keeps returning to the same thing: the cells release gently and the watering design avoids both spills and overwatering.
4. Bonviee 5-Pack Seed Trays with 12-LED Grow Lights - Built-In Lighting for Small Batches
Bonviee Seed Starter Trays with 12-LED Grow Lights, Clear, 5 Pack
12-LED full-spectrum light per tray
60 cells across five inserts
Vented elevated clear dome
USB powered
+ Pros
- Built-in 12-LED light on each tray removes the need for a separate lamp
- Vented elevated dome controls humidity as seedlings emerge
- Clear inserts and bases make root and moisture visible
- Drainage holes send water to the base for bottom watering
- USB power means no outlet per tray
- Cons
- No built-in timer so you need a timer or smart plug
- Power adapter not included
- 12-cell inserts are small for deep-rooted tomato seedlings
This kit exists to solve one problem: a gardener who wants to start tomatoes but does not want to buy a grow light. Each of the five trays carries its own full-spectrum 12-LED array, so a rack of windowsill trays is self-sufficient from day one.
The five 12-cell clear inserts give 60 planting spaces with drainage holes, and every surface is transparent. You can watch moisture and root development without lifting a lid or disturbing the medium. The elevated clear dome has vents, so you can move from sealed germination to partial airflow as the seedlings stretch.

Lighting Output and Timer Gaps
Twelve LEDs per tray is enough for a small batch of leafy crops and enough to keep tomato seedlings compact rather than leggy, provided you run them a decent number of hours a day. The kit is USB powered through an included one-to-five cable, and trays are compatible with seedling heat mats, which matters because tomato seed likes bottom heat for germination.
There is no timer in the box, and the power adapter is not included. You will need a 5V/2A supply or an existing USB port, plus a plug-in timer if you want a consistent photoperiod without remembering to switch it on. That is the most common complaint in buyer feedback, and it is easy to plan around.

Where the 12-Cell Size Hurts Tomatoes
Twelve cells is a small volume of mix. Tomato seedlings fill them quickly and need a second container well before planting out, so this is a germination-and-nursery kit rather than a long-term home. The clear viewing is genuinely useful in that window, because you can spot early damping-off the moment it appears.
Overall footprint is 5.7 x 8.5 x 5.5 inches per tray at 1.1 pounds, so five of them stack reasonably. Buyers like the all-in-one lighting and the clear root viewing, and note the vented domes help manage humidity. The missing adapter and lack of a timer are the recurring frictions.
5. 144-Cell Deep Six-Cell Trays - Best Budget Per Cell for Bulk Sowing
Seed Starter Trays, 144 Cells (24 Trays - 6 Cells Per Tray) + Plant Stakes
144 cells across 24 trays
Cells 1.5 inch square by 2.25 inch deep
Drainage slits in each tray
Fits standard 1020 trays
+ Pros
- Lowest cost per cell in the roundup with 144 cells included
- 2.25 inch deep cells give tomatoes real root room
- Drainage slits help prevent waterlogging
- Reusable and sized to fit standard 1020 trays
- Five plant stakes included for labeling
- Cons
- No humidity dome or lid included
- Black plastic means roots cannot be observed
- Six cells per insert means many trays to handle
Twenty-four six-cell trays add up to 144 cells, and every cell measures 1.5 inch square by 2.25 inch deep. That depth is the headline number here. Most cheap bulk trays are shallow, and shallow cells are exactly what push tomatoes into a root-bound state before they are ready to go outside.
These fit the standard 1020 footprint, so six inserts drop into a common base tray and you can bottom-water the whole set at once. Strategically placed drainage slits handle overwatering, and five plant stakes come in the box for labeling.

Why Cell Depth Beats Cell Count
A wider tray with shallow cells is not a better tray. Tomato roots push straight down, so a 1.5 inch square cell that is only an inch deep gives a seedling almost nowhere to go before roots circle and bind. At 2.25 inches you get a root ball that holds together at transplant, which is the single biggest factor in whether a seedling keeps growing or stalls for two weeks after you plant it.
Reviewers pick up on the depth first. Feedback regularly frames this as a bulk tray people recommend for large sowing batches, with the 2.25 inch cells named as the reason.

What You Give Up for the Volume
There is no dome. Nothing in this pack controls humidity, so if you need a sealed germination environment you have to source one separately. The plastic is black, which means you cannot watch roots develop. That is a real loss for tomatoes, since root color is the fastest signal that drainage is working.
Six cells per insert also means 24 separate pieces to fill, move, and wash instead of one or two trays. For a garden sowing 100 or more seedlings that scale is a benefit. For six tomato plants, you will use a fraction of the pack and store the rest, which is a normal trade with bulk inserts. Empty trays nest neatly inside a 1020 base in the meantime.
6. MIXC 5-Pack 200-Cell Clear Tray Kit - Best for Watching Roots Grow
MIXC 5 Pack Seed Starter Tray, 200Cell Mini Propagator Greenhouse Grow Kit
Clear 1.5 x 1.5 x 2 inch cells
Adjustable vents on domes
Stackable watertight bases
5 packs, 40 cells each
+ Pros
- Clear cells let you check root development before transplanting
- Adjustable vents help you avoid mold
- Rigid watertight bases support bottom watering
- Sturdy enough to reuse across seasons
- Compact footprint fits a windowsill or grow light
- Cons
- Plastic can warp in direct sun
- 1.5 inch square cells suit small seeds better than deep-rooted crops
- Occasional reports of domes arriving cracked
Five 40-cell trays in clear plastic, each with a vented dome and a matching base. The reason to pick this kit over a cheaper 40-cell pack is visibility. You can see whether roots have filled a cell, whether the mix has dried, and whether a cell is waterlogged, without tipping anything out.
For tomatoes that visibility pays off. Root color is the fastest way to spot that drainage is failing, and a clear cell shows it directly. The adjustable dome vents let you increase airflow once sprouts appear, which is the second most common way tomato seedlings are lost to damping-off.

Cell Dimensions and Dome Height
Each cell measures 1.5 x 1.5 x 2 inches and the dome adds 2.75 inches of headroom, giving a package that measures 14.57 x 9.02 x 5 inches overall. Two inches of cell depth is workable for tomatoes but not generous, so plan an up-potting step.
The bottom trays are rigid and watertight, which makes bottom watering straightforward and lets you carry a full tray to a sink without fear. They also stack before germination, so five kits occupy one footprint while they are setting up.

Sun Exposure and Warping
The most cited complaint in buyer feedback is plastic warping in direct sun. It is worth taking seriously, because a bowed tray stops sitting flat, water pools in one corner, and a tray that bows is also a tray that tips. We keep ours out of direct afternoon sun for exactly this reason, and anyone who hardens seedlings off outdoors should do the same.
The kit includes two garden tools and ten plant labels alongside five trays, five bases, and five domes. Owners like the clear cells and the vent control, and a minority report domes arriving cracked or damaged, so it is worth checking the domes as soon as the box opens.
7. Burpee XL Self-Watering 32-Cell System - Best for Travelers and Long Trips
Burpee XL Self-Watering Growing System Indoor Seed Starting 10" W x 20" L x 5" H, 1 Kit (32 Cells)
32 extra-large cells at 2.25 inch deep
Self-watering mat and reservoir
Includes coir pellets and dome
10 x 20 x 5 inch system
+ Pros
- Self-watering mat keeps cells moist for days without daily attention
- Extra-large 2.25 inch deep cells suit deep-rooted tomatoes
- Kits out complete with coir pellets stands markers and a dome
- Reduces overwatering risk and supports strong roots
- Cons
- Short dome that seedlings grow into and that slips off the tray edges
- Seedlings are hard to remove and the medium crumbles
- Trays feel flimsy once the reservoir is filled
This is the tray for anyone who starts tomato seeds and then leaves town for a few days. The self-watering mat draws from a water tray and keeps cells moist for days, which removes the single most common reason a seed tray fails while you are away.
The cells are extra-large at 2.25 x 2.25 x 2 inches across two 16-cell planting trays, and the manufacturer specifically calls deep cells ideal for tomatoes, peppers, and eggplants. Two plant stands lift the tray to let water drain back into the reservoir rather than sit against the base.

Self-Watering Mechanics Over Multiple Days
The mat sits between the reservoir and the cell bottoms, wicking moisture upward as the mix dries. That mechanism is what buys you a long weekend, and reviewer feedback reports strong germination results including tomatoes started from the included coir pellets.
Because the system is capillary rather than drip, you still need to check it. If the reservoir empties completely the mat can dry out and stay dry, so topping it up before you travel matters more than it would with a hand-watered tray.

Where the System Falls Short
The dome is the main problem. It is short, it slips off the tray edges, and it can crush seedlings at the edges when it moves. Buyers report this repeatedly, and it is the reason this kit scores lowest on rating in the roundup despite strong features elsewhere.
There is a second, subtler issue. Extracting seedlings from the cells is difficult and the medium tends to crumble, which is the opposite of the silicone trays in this list. The trays also feel flimsy once the reservoir is filled with water, and the coir pellets need hot water and effort to fully expand. For travel, the reservoir is worth it. For transplant-day handling, choose silicone instead.
8. SOLIGT Thick Plastic 3-Set with 5-Inch Domes - Best Tray for Durability
SOLIGT Thick Plastic 3-Set Strong Seed Starter Trays with 5" Humidity Domes
Thick heavy-duty reusable plastic
3 trays and 3 tall domes
144 cells total
Two vents per dome
+ Pros
- Noticeably thicker and sturdier plastic than most trays we tested
- 5 inch domes give tall seedlings real headroom
- Medium size is easy to carry and fits a windowsill
- Two adjustable vents per dome control airflow
- Tight seal holds warmth and humidity
- Cons
- Standard 1020 soil trays are not included and must be bought separately
- Highest-priced item in this roundup
- Lids can pop off when the unit is moved around
Buy this one if tray warping is the failure mode you have already experienced. The plastic is visibly thicker than everything else we used, and thickness is the entire defense against bowing. A thin tray that bows spills mix and tips seedlings; a thick tray does neither.
Each of the three units pairs a starter tray with a matching 5-inch-tall humidity dome, and each tray holds 48 six-cell trays for 144 cells total. The tall dome is a genuine advantage for tomatoes, which grow upright and fast under a grow light and hit a low cover sooner than gardeners expect.

Plastic Thickness and Long-Term Reuse
This set has the highest rating in our roundup at 4.6 across more than 2500 reviews, and the feedback explains why: people bought it for build quality rather than cell count. Reviewers describe the plastic as thicker and stronger than other trays, and report it lasting many seasons with reuse.
That matters for the durability question specifically. The most common complaint across seed-tray forums is trays deforming or cracking after a single season of sun exposure, and the answer is not a different brand, it is wall thickness and a habit of keeping trays out of direct sun when they are empty.

Sizing, Vents, and What Is Not Included
Inner space measures 13.7 x 10 x 6 inches, so the units are medium-sized rather than full 1020 flats. Reviewers consistently like that they are easy to carry and still fit a windowsill, with two adjustable clear vents per dome for airflow and light penetration.
One purchasing caveat appears over and over: the standard soil trays shown in product photos are not included and must be bought separately. It is also the highest-priced item here, so budget for the six-cell inserts as well. Lids can pop off if the unit is moved often, so carry it by the base.
9. 300 Deep Extra-Large Cells - Best Tray for the Deepest Taproot Room
AAAmercantile Seed Starter Trays 300 DEEP Extra Large Cells Total (50 Trays of 6 Cells Each)
3 inch deep cells across 300 total
Cells 2.5 x 2.25 x 3 inches
Flexible cells for easy release
Six trays fit a 1020 tray
+ Pros
- Deepest cells in this roundup at 3 inches for tomato taproots
- Flexible construction makes de-potting and root release easier
- Huge 300 cell capacity in one pack
- Six-cell trays fit a standard 1020 tray for flexible batch sizing
- Cons
- Manufacturer considers the trays generally single use
- No humidity dome or lid included
This is the tray to buy if your complaint is that tomatoes go root-bound before you can plant them out. Cells measure 2.5 x 2.25 x 3 inches, which is the deepest in this roundup by a full inch over the next deepest option, and 50 six-cell trays give you 300 cells.
The cell walls are flexible by design. You squeeze the bottom and the seedling comes out with a coherent root ball instead of being pried out of a rigid cone, which is the same advantage the silicone trays offer without the silicone price.

Three Inches of Depth and What It Buys You
Tomato seedlings form a taproot that drives straight down. Give it three inches of straight-sided column and you can hold a seedling through its entire indoor phase, up-pot it once if you want extra root area, and plant it out at a good size. Give it one inch and you get a seedling that circles its cell, hardens off badly, and stalls after transplanting.
Buyer feedback matches the spec sheet: users value the 3 inch cells for allowing larger root systems before transplanting, and they single out the flexible plastic for easier de-potting. The 4.6 rating reflects a simple product doing one thing well.

Trade-Offs: Volume Instead of Versatility
There is no dome, no base reservoir, and no lighting. This is a bare tray, and buying 300 cells when you want 12 plants means storing a lot of plastic. On the other hand, six of these six-cell trays fit inside a standard 1020 tray, so you can set up exactly the batch size you need and leave the rest of the pack nested.
The one real caution is the manufacturer's own position that these trays are generally considered single use. The flexible construction will not snap, but thin plastic that has been flexed a dozen times eventually tears. If you want a tray you keep for a decade, this is not it.
10. Ryscam 72-Cell Silicone Kit with 4.33-Inch Dome - Best Flexible Multi-Cell Set
Seed Starter Tray, 72 Cells Indoor Seed Starter Kit, Flexible Silicone Designed Seedling Starter...
72 cells with silicone pop-out bottoms
4.33 inch tall lid and dome
Grooved drainage design
BPA-free, dishwasher safe
+ Pros
- Silicone bottoms pop seedlings out in one intact soil cube
- Tall 4.33 inch lid gives room before hardening off
- Adjustable vents move from sealed germination to airflow
- Base tray doubles as a simple water reservoir
- Flexible plastic that should last many seasons
- Cons
- Cells are small so seedlings need transplanting
- One reviewer reported lids that do not fit properly
- Not suited to starting hundreds of plants at once
Seventy-two cells is the batch size most tomato growers actually want, and this kit pairs that count with flexible silicone cell bottoms. Push from underneath and the seedling releases as one soil cube, which is close to the least disruptive removal you can get from a cell tray.
The lid and humidity dome stand 4.33 inches tall, which is generous headroom compared with most domed kits. That matters for tomatoes because leggy seedlings are the usual result of a cover that gets reached too early. Vents let you open things up gradually once sprouts appear.

Release Mechanics and Drainage Grooves
Grooves in the cell bottoms improve drainage and aeration, and deeper grooves in the base draw excess water away from the cells. A raised rim contains water so you can bottom-water without it creeping across your shelf. The base tray doubles as a simple reservoir, which is a sensible design at this cell count.
Buyer feedback puts the release behavior first. People buying this kit care most about how cleanly a seedling comes out, because tomatoes dislike root disturbance, and that is the feature the reviews single out again and again.

Cell Size and Batch Limits
Individual cells are small, so seedlings will need a transplant into something larger before planting out. At 72 cells this is a good unit for two or three tomato varieties rather than a whole block of one. One reviewer also reported lids that do not fit properly, so check the closure on arrival rather than trusting it.
Material is BPA-free polypropylene and silicone, reusable and recyclable after transplanting, and dishwasher safe. The footprint is 7.87 x 6.29 x 6.29 inches, and the kit includes ten labels and two planting tools for digging, loosening, and transplanting. Reviewers report the plastic is well made and not brittle, which is what you want from a flexible tray.
How Deep Should a Seedling Tray Be for Tomatoes?
Look for a cell depth of at least 2 inches for tomatoes, and 2.25 inches or deeper if you can. Tomato seedlings send a taproot straight down rather than spreading sideways, so depth is the dimension that matters most. Shallow cells force roots to circle and bind, and a root-bound tomato seedling tends to stall for weeks after you plant it out.
The tomato root system develops fast indoors. Between germination and the six-to-eight-week mark, a healthy seedling is putting on the vertical root mass that will anchor it in the garden. A cell that is one inch deep simply cannot hold that root, which is the single most common reason healthy-looking tomato seedlings fail after transplant.
The practical rule we use: if you cannot buy a tray at least 2 inches deep, buy a shallower tray and plan to up-pot. Twelve-cell and twenty-four-cell kits are fine for germination. They are the wrong tool for holding a tomato until planting day, and no amount of light compensates for the root restriction.
Which Cell Count Should You Buy?
Match the count to the number of plants, then add a margin. Tomato germination is not perfect, and you will lose a few seeds to damping-off no matter how careful you are. Sow about twice what you intend to transplant.
- 24 cells: Best for 6 to 12 tomato plants with a comfortable margin. Big cells, more root room per seedling, less crowding. Our pick for anyone starting a handful of varieties.
- 36 to 40 cells: The sweet spot for most home gardens. Enough capacity for two or three varieties plus backups, with cells that still transplant cleanly.
- 72 cells: The standard for 24 to 36 tomato plants. This is the size most growers describe as their default, and it matches well with later up-potting into larger containers.
- 128 to 200 cells and above: For market-scale or large-garden sowing. Beyond about 200, seedlings usually outgrow the cells before you can use the tray, so depth matters more than count.
If you only want six tomato plants, a 72-cell tray still works fine. Growers do it constantly and use a fraction of the cells. The trick is sowing only what you need and leaving unused cells empty rather than filling every cell because it is there.
Tray Materials: Plastic, Silicone, and Biodegradable Pots
Plastic cell trays dominate because they are cheap, rigid, and universally compatible with 1020 base trays. Silicone trays trade rigidity for gentle root release, letting you unpot a seedling in one piece instead of prying it loose. Biodegradable peat and fiber pots trade everything for disposal convenience, since you plant the pot and it breaks down in the soil.
For tomatoes specifically, silicone wins on transplant shock and rigid plastic wins on cost and base-tray compatibility. The tradeoff most people do not expect is mold. Rigid plastic cells trap moisture against the mix, and a tray that is never properly sanitized between crops carries damping-off pathogens forward. Silicone is easier to scrub clean and is dishwasher safe in the kits we tested.
Biodegradable pots are the one option we would use sparingly for tomatoes. Peat and fiber pots decompose into the root ball, so a tomato that is not removed promptly stays constricted, which defeats the point of a deep cell in the first place.
The 1020 Tray Footprint and Why Up-Potting Containers Matter
A 1020 tray is the 10 x 20 inch standard footprint that nearly every insert on the market is built to fit. It is the closest thing seed starting has to a universal standard, and buying into that ecosystem pays off the moment you need to move seedlings.
Here is the problem 1020 solves. Tomato seedlings grown in small cells need a bigger container before planting out, and the containers people improvise with, plastic cups and solo cups, are top-heavy. They tip over during hardening off, and a tray of tipped seedlings is a tray you are re-potting from scratch.
The fix is to up-pot into cells that fit inside the same 1020 tray, so the whole batch still moves as one unit from the windowsill to the porch to the garden. Several of the trays we tested support this directly. The 144-cell deep inserts and the 300 deep six-cell trays both drop six inserts into a standard 1020 base, and the Burpee XL system is built to that footprint from the start.
Our approach is to keep one 1020 base permanently in service and swap inserts into it. Storage logistics are the boring half of seed starting, and we keep our gear in a stackable setup like the one we describe in our cup holder tray guide so nothing ends up scattered across a closet.
Mistakes That Ruin Tomato Seedlings
- Leaving the dome on too long. Once sprouts appear, a sealed cover traps humidity and encourages damping-off. Open the vents, then remove the dome entirely within a day or two.
- Watering from overhead. Pouring water over the cells splashes mix out and knocks seedlings flat. Fill the base tray and let the mix wick it up.
- Choosing cells that are too shallow. Under 2 inches of depth and tomatoes go root-bound before they are ready to plant.
- Filling every cell because it is there. A 72-cell tray is not a reason to grow 72 tomato plants. Sow what you will actually transplant.
- Leaving trays in direct sun while empty. UV exposure is the leading cause of warping and cracking. Store trays indoors between seasons.
- Reusing trays without sanitizing. Soil-borne tomato pathogens survive on plastic surfaces between crops.
Cleaning, Storing, and Reusing Trays Between Tomato Crops
Most trays are reusable, and reviewers repeatedly describe trays they have kept for many seasons. That only holds if you clean them properly, because tomato soil carries pathogens that survive a light rinse.
Wash trays with hot water and dish soap, then sanitize before the next tomato crop with a dilute bleach solution, about one part household bleach to nine parts water. Rinse thoroughly and let them dry fully in the air. Dishwasher-safe silicone trays can go in the top rack instead, which is the easiest option if you own one.
Let everything dry completely before nesting. Trays stacked damp grow algae and mold in the channels, and a tray that smells musty when you fill it will do the same thing to your next batch of seeds. Store flat or nested in an indoor closet rather than on a porch, and keep them out of direct sun between seasons.
Frequently Asked Questions
What are the best seedling starter trays?
The best seedling starter trays for tomatoes combine cells at least 2 inches deep with drainage holes in every cell and a rigid enough frame to move when wet. Our top pick is the MIXC 10-Pack 120-Cell Kit for its complete tray, base, dome, and label set, the Gardzen 5-Set 200-Cell Kit is the best value, and the Burpee SuperSeed 36-Cell Silicone Tray releases roots with the least damage.
How deep should seed starting trays be?
At least 2 inches for tomatoes, and 2.25 inches or more if you can find it. Tomato seedlings drive a taproot straight downward, so cell depth is the dimension that prevents root-binding. Anything under about 1.5 inches will produce a root-bound seedling that often stalls for weeks after transplanting.
Should I use plastic or silicone seed trays?
Rigid plastic wins on cost and fits standard 1020 base trays for bottom watering, while silicone wins on transplant day because flexible cells release seedlings with the roots intact. For tomatoes, silicone reduces transplant shock and rigid plastic maximizes batch size per dollar. Many growers keep both and use each for a different stage.
Can I reuse seed trays for tomatoes every year?
Yes, provided you sanitize them between tomato crops. Wash with hot soapy water, then treat with a dilute bleach solution of roughly one part bleach to nine parts water, rinse, and dry fully before storing. Trays stored indoors out of direct sun last many seasons, while trays left in sunlight tend to warp and crack after a season or two.
What are the most common tomato seed starting mistakes?
The biggest mistakes are leaving a humidity dome on after emergence, watering from overhead instead of filling the base tray, using cells under 2 inches deep, and sowing every cell of a large tray. A fourth common error is reusing trays without sanitizing, which carries damping-off and soil-borne tomato pathogens into the next crop.
Which Tomato Seedling Tray Should You Buy?
If you want one tray that does everything without a learning curve, the MIXC 10-Pack 120-Cell Kit is the pick, because the trays, watertight bases, vented domes, and labels all arrive together. If you want the most tomato capacity for the money and a good batch size per unit, the Gardzen 5-Set 200-Cell Kits win, with 40 cells per tray and a tight dome seal. If transplant shock is what worries you most, the Burpee SuperSeed 36-Cell Silicone Tray is the answer, since the flexible cells release seedlings in one piece.
For depth specifically, the 144-Cell Deep Six-Cell Trays and the 300 Deep Extra-Large Cells put 2.25 and 3 inches of root room under every seedling, which is where tomatoes reward you. For durability, the SOLIGT Thick Plastic 3-Set is the one that will not bow in the sun. For a windowsill with no separate lamp, the Bonviee 5-Pack with 12-LED lights is worth the extra setup steps. For gardeners who travel, the Burpee XL Self-Watering System covers days away at the cost of a lid that slips. And for a 72-cell batch with generous headroom, the Ryscam silicone kit does it well.
Whichever you choose, buy for depth first, keep trays out of direct sun when they are empty, and sanitize before the next tomato crop. That habit is worth more than any tray on this list.









