Seed starting basics

29 Apr.,2024

 

Seed starting basics

By Aaron French

For more information, please visit 32 cell seedling trays.


If you’re at all like me, you’ve recently been daydreaming about growing a lush summer garden. Winter is a great time to reflect on all the amazing produce you grew last year and to get excited about the upcoming growing season. It's also a time to look for something to… up your game. Something to take your gardening experience to the next level.


Might I recommend starting your own seeds? I know, I know...it seems so daunting! You might be asking yourself: “Where would I even start seeds in my apartment?”, “How can I get all the materials?” or “Isn’t that super hard and complicated?”. The answers to all those questions and more are below!



Seed starting is super simple and can be done almost anywhere (sorry, but probably not in your dark basement). Materials wise, all you need are seeds, containers, and propagation media—which is a fancy term for the mixture you plant seeds into. Let's break down each section further:


Seeds: This one’s obvious. You’ll only need to start transplants of vegetable varieties that need an extended growing period. For example, radishes are direct-sown, meaning the seeds are placed directly into the growing area at the time of planting. For a full list of what’s usually grown as a transplant vs direct sown, check out this helpful planting chart from High Mowing Organic Seeds.




Containers: In the industrial greenhouse industry, plastic is pretty standard. The products below are low cost and available from most big box garden centers.



1020 Tray: Named for its rough dimensions (10”x20”), this tray is generally used as support for plug trays, or other smaller-celled containers, like commercial 6 packs. It could also be filled with potting media and seeded directly.




Plug Trays: Often used in conjunction with a 1020 tray, these molded plastic-celled trays are easy to fill, plant, and seed. The number of cells in a tray varies, as does the corresponding size of the cell. A 50-cell plug-tray will have much larger cells than a 128-cell tray. These are often referred to by the number of cells, and 72’s are the most versatile and popular as they’re great for starting everything from lettuce to cauliflower.




Form Trays: Normally used in conjunction with small plastic pots for the purposes of “up-potting” small seedlings. Up-potting is the simple practice of moving a small seedling to a larger container, allowing it to grow more and build a stronger root structure. These form trays come in a variety of sizes, but 32 (spots for pots) are standard.

Contact us to discuss your requirements of 15 Cells Garden Starter Trays. Our experienced sales team can help you identify the options that best suit your needs.


Pots: Small, molded plastic pots used for up-potting from plug trays. Measured in inches, these pots are perfect for helping vegetable plants reach pre-planting maturity. Make sure to get the size that corresponds with the form tray. 32 celled form trays use 2.5” pots.


Propagation Media: The most important piece in your seed starting journey. Most potting media doesn’t actually contain soil, as they are optimized for germination and shorter-term growth. Instead, they’re mostly made up of peat moss, perlite, and compost. You can buy a prepared mix at most garden centers, or make your own! A great guide for making your own (and choosing a commercial mix) can be found here, courtesy of ATTRA. It’ll help if you get the potting mix thoroughly wet before filling your plug trays or pots. Consistent moisture is crucial for germination and seedling growth, so make sure to keep your young plants quenched!


With these three things, you’re almost set! While seeds don’t actually need light to germinate, they do need a healthy dose of it almost immediately after the radicle (beginning of a root) and epicotyl (beginning of the stem and leaf structure) emerge. A south-facing window or enclosed porch would work great for putting your trays on. A young plant needs approximately 10-12 hours of sunlight a day, so get them there early and make sure to rotate the tray to keep the plants from leaning too much towards the sun in one direction. If you’re lucky enough to have grow-lights as part of your gardening setup, you’ll want to keep them on for around 12 hours a day and generally keep them only a few inches from the tops of your plants.


We don’t quite have space in this post to cover things that can help your seed starting journey become more successful, but look for another post covering some supplemental info on heating mats, fertilization, up-potting, and hardening off!


Here's a little video on how City Sprouts does our seed starting


The Best Seed Starting Trays

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While it’s possible to purchase either seedlings or mature plants at a nursery, for many gardeners, it’s more rewarding to start plants from seed. A number of supplies are needed to sow seeds at home, and one of the most essential is a seed starting tray.

Shopping for the best seed starter trays online, however, can be somewhat challenging because there are so many options available at a wide range of prices. Seed trays come in several styles and can be made with a variety of materials. To help navigate the ample choices, this article breaks down what to look for when shopping for the best seed starter tray and includes our curated picks for some of the best seed planting trays.

Photo: amazon.com

What to Consider When Choosing the Best Seed Starting Tray

Though it’s easy to assume that all plant starter trays offer similar performance, a number of factors affect their functionality. Keep reading to learn about some important features to consider when choosing the best seed starting supplies.

Material

A primary consideration when choosing seed starter trays is the material. Generally speaking, seed trays usually fall into two general categories: reusable or biodegradable.

  • Reusable plastic seed starter trays are a popular choice because they’re durable, lightweight, and reusable. Since they can be used repeatedly, they’re economical, making them ideal for experienced gardeners who start seeds year after year. One downside is that the seedlings must be removed from the tray before they are planted. For organic vegetable gardening, opt for trays made from BPA-free plastic.
  • Biodegradable seed starter trays are typically made from peat and can be planted directly into soil without removing the seedlings. The material degrades quickly once planted, allowing the plants’ roots to grow into the soil. This also helps to ensure that the plants don’t experience transplant shock.

Capacity

A seed tray’s capacity is dependent on the number of cells it has. Small seed trays may only have four cells, while large models can have up to 70. Smaller trays can be arranged together in a variety of configurations to fit under grow lights, while larger trays are better suited to large growing stations.

If using natural light rather than grow lights, it’s best to opt for trays that are small enough to fit on a windowsill. Choose trays based on the capacity needed for your particular situation.

Cell Size and Depth

Another consideration when choosing seed trays is the size of each individual cell. Seed tray cells have a standard size of 1.5 inches long by 1.5 inches wide. Their depth ranges from 1.5 to 2.5 inches.

Seedling trays tend to be deeper and can accommodate more mature seedlings and plants with deeper root systems. It’s not advisable to choose a tray with cells deeper than 3 inches because they aren’t ideal for water drainage.

Accessories

While seed starting trays are sometimes sold without any extras, some include useful accessories.

  • Domed lids are made from clear plastic and allow gardeners to monitor the plants’ progress while controlling the temperature and keeping the soil damp. Some domed lids are vented to provide additional humidity control.
  • Base trays are designed to be used underneath cell trays and allow users to either catch water drainage or water the seeds from below.
  • Watering mats function similarly to base trays but are designed to further aid in water being drawn up into the cell tray.
  • Heating mats help to control the soil’s temperature and are particularly useful in cold climates.
  • Labels come in handy to ensure growers can keep track of all the seeds they’ve planted.

Our Top Picks

Now that you’ve learned a bit about grow trays, it’s time to start shopping. The following are our top picks for some of the best seedling starter trays for your home garden.

Best Overall

Gardzen 40-Cell Plant Tray

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This seed starter kit comes with almost everything gardners need to start a large collection of plants. It includes five plastic trays, each of which holds 40 seedlings. Each cell has a hole at the bottom to allow drainage. Base trays are included with the kit, so they don’t need to be purchased separately. Domed lids are also included, which are 2.75 inches tall, allowing for seedlings to grow under ideal temperature conditions.

Each cell is 1.4 inches long by 1.4 inches wide by 1.85 inches deep, which is slightly shallower than average, so it’s important to transfer the seedlings into larger containers (or a garden bed) before they outgrow their cells.

Product Specs

  • Material: Plastic
  • Number of cells: 200 (40 by 5)
  • Tray dimensions: 14.5 inches long by 9 inches wide by 1.85 inches deep

Pros

  • Comes in a pack of 5
  • Made with reusable plastic
  • Comes with base trays and domed lids
  • Extraction tools are included

Cons

  • Shallow cells

Get the Gardzen seed starting trays on Amazon or Gardzen.

Best Bang For The Buck

Aifusi 10-Pack Seed Starter Kit

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Those looking to start a large number of seeds without making a major financial investment may want to consider this kit from Aifusi. The trays are sold in a pack of 10, each of which contains 72 cells, for a total of 720. The cells are each 1.5 inch long by 1.5 inch wide with a depth of 1.57 inches. Drainage holes prevent water from accumulating at the bottom of the cells.

The trays are made from thick BPA-free plastic, meaning they can be reused year after year and are suitable for organic vegetable gardening. While these trays offer a large capacity for growing, they don’t come with any accessories. Base trays will need to be purchased separately.

Product Specs

  • Material: Plastic
  • Number of cells: 720 (72 by 10)
  • Tray dimensions: 21.1 inches long by 10.9 inches wide by 1.57 inches deep

Pros

  • Affordable price
  • Comes in a pack of 10
  • Durable and reusable
  • Made with BPA-free plastic

Cons

  • Shallow cells
  • Accessories not included

Get the Aifusi seed starting tray kit on Amazon.

Best Self-Watering

Burpee 32-Cell Self-Watering Ultimate Grow System

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Beginners may appreciate how easy it is to germinate seedlings with this self-watering grow kit from Burpee. It comes with the brand’s coconut coir pellets, which are designed to be placed in the bottom of each cell and moistened with water before adding soil. The pellets then slowly release water over time.

The kit comes with two trays (each of which has 16 cells), 32 growing pellets, a clear greenhouse dome, a self-watering mat, a base tray, and six plant markers. The cells are extra large and each one is 2.25 inches long by 2.25 inches wide by 2 inches deep, providing each plant plenty of room to grow.

Product Specs

  • Material: Plastic
  • Number of cells: 32 (16 in each tray)
  • Tray dimensions: 20 inches long by 10 inches wide by 2 inches deep

Pros

  • Made with large cells
  • Includes a base tray and greenhouse lid
  • Easy-to-use self-watering design

Cons

  • High price

Get the Burpee Self-Watering seed starting trays on Amazon.

Best Domed

Bonviee 10-Pack Seed Starter Trays

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While there are plenty of seed tray options on the market that come with domed plastic lids, not all of them feature humidity control. This model from Bonviee has a clear lid with a vent that allows users to decide on the humidity level that’s ideal for their plants. The trays come in a pack of 10, each of which has a matching domed lid.

Each tray is small at about 6.1 inches long by 4.4 inches wide, but the cells are 2 inches deep, giving seedlings room to grow their root systems. The kit also includes base trays and plant labels.

Product Specs

  • Material: Plastic
  • Number of cells: 120 (12 by 10)
  • Tray dimensions: 6.1 inches long by 4.4 inches wide by 2 inches deep

Pros

  • Affordable price
  • Includes vented domed lids
  • Designed to accommodate coconut coir pellets

Cons

  • Small trays

Get the Bonviee seed starting trays on Amazon.

Best Biodegradable

Eco Pots Seed Starter Trays

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Plastic seed starter trays are convenient because they can be reused season after season, but they can’t be planted directly in the ground like biodegradable trays. This model from Eco Pots is made from 100 percent recycled paper and is designed to biodegrade quickly after being planted, allowing the plants’ roots to expand and preventing transplantation shock.

The kit comes with 10 trays (each of which has 10 cells), 10 plant markers, and a couple of tools to facilitate transplanting the seedlings as needed. Each tray is 8.5 inches long by 3.5 inches wide, and each cell is a 1.35-inch square and 1.75 inches inches deep.

Product Specs

  • Material: Recycled paper
  • Number of cells: 100 (10 by 10)
  • Tray dimensions: 8.5 inches long by 3.5 inches wide by 1.75 inches deep

Pros

  • Made with eco-friendly recycled paper
  • Completely biodegradable trays
  • Prevents transplantation shock

Cons

  • Accessories are not biodegradable

Get the Eco Pots seed starting trays on Amazon.

Best Reusable

Burpee SuperSeed Seed Starting Tray

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This upgraded seed starting tray from Burpee is designed for repeated use and offers a number of features that can’t be found on standard plastic seed trays. The flexible cells are designed to gently pop out the seedlings and soil when it’s time to transplant them, which helps to avoid tearing delicate roots.

Each cell has molded corner slots, which improve both drainage and soil aeration, and the watering tray features deep channels that draw excess water away from the cells. The material is even dishwasher-safe, making the tray easy to clean between uses. Only one tray is included, which includes 16 large cells.

Product Specs

  • Material: Plastic
  • Number of cells: 16 (4 by 4)
  • Tray dimensions: 11.5 inches long by 10.5 inches wide by 2.5 inches deep

Pros

  • Flexible cells make for easy transplanting
  • Designed to prevent water buildup
  • Made with dishwasher-safe material

Cons

  • High price per cell

Get the Burpee SuperSeed seed starting trays on Amazon.

Best Kit

Jiffy 36 Peat Pellet Seed-Starting Greenhouse Kit

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This kit from Jiffy is perfect for first-time seed germinators because it comes with peat pellets, fertilizer, a domed lid, and a base tray. What sets this kit apart is that there are no individual cells. Preferable for some home gardeners, the cell-less setup means the seedlings don’t need to be extracted individually when it’s time to transplant them.

To use, start by placing the pellets in the base tray and adding 1.5 inches of warm water. Once the pellets have expanded to 1.5 inches in height, the water can be drained. Users must then peel back the netting on each pellet to insert several seeds into each one. No additional soil is needed.

Product Specs

  • Material: Plastic
  • Number of cells: 36 (6 by 6)
  • Tray dimensions: 11 inches long by 11 inches wide by 2 inches deep

Pros

  • Includes biodegradable peat pellets and fertilizer
  • Comes with a domed lid
  • No additional soil is required

Cons

  • Lacks cells to separate seedlings

Get the Jiffy seed starting tray kit at The Home Depot.

Our Verdict

Having read this guide, you may already know which seed starting tray is best for your needs. If not, we recommend the Gardzen seed starting trays as our top pick for most typical home gardeners because it’s cost-effective and comprehensive. Those on a budget may appreciate the Aifusi seed starting tray kit, which is a great choice at a lower price point.

How We Chose the Best Seed Starting Trays

Years of experience covering home improvement and gardening as well as extensive product research went into creating this guide on the best seed starting trays. We explored more than 25 seed tray options and weighed a number of practical considerations before making our recommendations.

  • Material: Both plastic and biodegradable seed trays have their own advantages, so we opted to include examples of both among our recommendations.
  • Capacity: Seed starting trays vary widely when it comes to their capacity. We included both large and small trays in our top picks in order to provide options for most home gardeners.
  • Cell size: Cell sizes on seed starting trays vary, but we opted to exclude any trays with depths of more than 3 inches because they tend to drain poorly.

Advantages of Using Seed Starting Trays

While it’s possible to germinate seeds in nearly any kind of container, using a seed starting tray makes the process simpler, tidier, and easier to maintain. Here are some advantages of using a seed starting tray.

  • Seed trays line up the seedlings in rows, making them easier to heat or water evenly.
  • Seed trays are easy to move around and can be brought outdoors once the weather is favorable.
  • Seed trays feature drainage holes, which allow the soil or seed starting mix to drain effectively.

FAQs

While you now know more about choosing the best seed starting kit, you may still be looking for more information. Here are answers to some of the most frequently asked questions about seed starter trays.

Q. How many seedling trays do I need?

The number of seedling trays needed depends on the number of seeds you wish to plant.

Q. How do I choose a seedling tray?

First, decide whether you want a reusable or biodegradable tray. Then, choose a tray with a size and capacity that best suits your needs.

Q. What do I put under seed starting trays?

A base tray should be placed under a seed starting tray to catch the water that drains out of the holes in the cell tray.

Q. How do I remove seedlings from trays for planting?

To remove seedlings from a plastic tray for planting, turn the tray upside down and gently squeeze each cell to remove the seedling. Never pull on the seedling’s stem in order to remove it. If needed, use a butter knife to help detach the soil from the cell tray.

Q. What helps seeds germinate faster?

In order to help seeds germinate faster, some gardeners opt to soak their seeds in warm water for 24 hours before planting them.

Q. What is the ideal temperature for healthy seedling growth?

The ideal temperature for seedlings varies based on the plant variety. Generally speaking, however, most seedlings thrive at temperatures between 65 and 75 degrees Fahrenheit.

Q. Does starting seeds save money?

Yes. Starting seeds is an economical choice because buying seeds is more cost-effective than buying seedlings or mature plants.

Are you interested in learning more about 48 Holes Seedling Starter Kit? Contact us today to secure an expert consultation!