The Beginner Guide To Seed Starting Trays

Last Updated June 8, 2021 By Bella Zinti

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Looking to take your gardening skills to the next level? It's time to stop overpaying for starter plants and start growing your own seedlings using seed starting trays.

In this guide, we will help you navigate and teach you everything you need to know about growing plants from seed.

What Are Seed Starting Trays?

Seed starting trays are a gardening tool specifically created for starting plants from seed. Most are a plastic tray with small cells or cups designed to hold seedlings and a clear domed lid.

In addition to streamlining the seed starting and planting process, they also offer the perfect conditions for seeds to germinate and grow until they're ready to be translated into your flower beds, home garden, or planters and pots.

Benefits Of Using Seed Trays

As any green-thumbed gardener will tell you, seed starting trays are one of the most helpful pieces of gardening equipment you can own. To help you understand why to choose seed trays, here are a few of the many benefits of using seed trays over planting in larger pots or containers:

  • Creates the Ideal Conditions for Seed Starting— The containers are designed specifically for starting seeds and offer the perfect soil temperature and moisture, humidity level, and water drainage for early plant growth.
  • Keeps Seeds Contained and Organized— The tray cells keep the seeds contained while offering just enough space to sprout. Plus, it makes them incredibly simple to organize, monitor during growth, and carry to your garden when it comes time to plant.
  • Ensures Even Distribution of Water and Nutrients— Using seedling trays provides growers with greater control of the starting process and ensures each plant receives an adequate amount of water and nutrients.
  • Speeds Up The Germination Process— By providing the ideal conditions for new seedlings, the trays can help seeds germinate at a faster rate. In addition, some trays come equipped with heating pads that help to further speed up the germination process.
  • Makes Seedlings Easier to Transplant— Seed starter trays make transplanting simple, as each cell contains a single plantAdditionally, some trays are made with biodegradable materials that can be planted directly into the ground.
  • Reusable, Environmentally-Friendly, and Economical— Seed starting trays are available at nearly every garden center or home improvement store at an affordable price. Plus, most seedling containers are reusable, meaning you won't need to spend money each planting season on new supplies.

How To Use Seed Starting Trays

While using seed starting trays is a pretty straightforward process, you'll still want to reference the instructions on the package of seeds to ensure you create the right conditions for that specific plant. Here is a brief overview of how to plant seedlings in a starter tray:

  • Start by filling each cell with your preferred seed starting mix, or potting soil.
  • Next, plant one to two seeds in each of the cells. Typically seeds should be planted just on or below the surface of the soil.
  • Lightly water the plants, double-checking that each cell is draining properly. The soil should be moist but not soggy.
  • Place the flats under a grow light or in a warm, well-lit area inside your house.
  • Water regularly to keep the soil moist and prevent it from drying out as your seedlings sprout and grow.
  • Once your seedlings have reached an adequate size for planting, they'll need to be hardened off before they're placed in the ground or in pots.

How To Clean Seed Starting Trays

If you plan on reusing your plastic trays, you'll need to clean and disinfect your supplies between each use to prevent a common seedling problem called damping-off or seedling blight. The preventable soil-borne disease can stunt plant growth or prevent seeds from sprouting entirely. Here are step-by-step instructions for how to care for your trays:

  • First, you'll need to gather your supplies: a large bucket or bin, paper towels, bleach, and dish soap.
  • Start by wiping or rinsing out any loose soil leftover in each cell. You may need to soak the tray first to loosen dry, caked-on dirt.
  • Next, fill the bucket with warm water and a splash of bleach. Add the trays and soak them for fifteen to twenty minutes to kill off any bacteria or diseases. Depending on the size of the tray, you may need to flip it over halfway through to disinfect the whole thing.
  • Finally, rinse the trays with plain water and allow them to air out before reusing them.

How To Water Seed Starting Trays

Correctly watering your seedling trays is crucial to growing strong, healthy plants. Too much water and your seeds will rot, too little, and they won't germinate properly. Here are a few helpful tips on how to water seed starting trays:

  • Most seeds need to be watered at least once per day to prevent the soil from drying out. In hot, dry climates, they may need to be watered more than once per day.
  • Proper drainage is key to successfully growing seeds. Be sure to purchase a product that comes equipped with a drainage hole in each cell.
  • While you'll want to cover your trays with a clear domed lid or some loose plastic to create a warm, humid greenhouse environment, it's important to remove the lid and air the seeds out to prevent them from getting moldy.
  • To prevent overwatering, try using a spray bottle or watering from the bottom.

The Best Seed Starter Trays

EarlyGrow Medium Domed Propagation Trays

EarlyGrow Medium Domed Propagation Trays

EarlyGrow's Medium Domed Propagation trays help maintain the optimal humidity, ventilation, temperature, and moisture level for growing plants from seed. Plus, they keep plants contained and make it effortless to move mature plants to and from your garden. They're made of high-quality, durable materials that won't shatter or splinter and can be reused year after year. In addition, the clear domed lid is made with a new and improved material that is extra resistant to warping and cracks.

The medium-sized tray measures 15 in x 9 in x 7 in and is available with side extenders to accommodate larger plants.

Judith Bloom Seed Self-Watering Seedling Tray

Starting seedlings at home is easy with Judith Bloom's Self-Watering Seedling Tray! It's made with eco-friendly terracotta that's reusable and BPA-free. The all-natural material won't break, crack or crumble like other low-quality plastics and terracotta pots. Plus, the minimalist design looks stylish on your window sill, table, or patio.

The versatile tray is perfect for starting vegetables, flowers, herbs, and spices for your backyard garden. It measures 7.75 in x 5.25 in x 3.5 in and features ten cells, each of which comes equipped with a small drainage hole.

Daniel's Plants Plantable Seed Starter Trays

Searching for environmentally-friendly trays that are versatile and simple to use? Look no further than Daniel's Plants Plantable Seed Starter Trays! They're made from 100% natural and biodegradable materials that can be planted directly into the ground to promote proper aeration and prevent plants from going into shock during transplantation.

Each kit comes with ten seedling trays that can grow a total of one hundred seedlings. The 1.75 in cells are the perfect size for starting flowers or veggies like peppers, cucumbers, and tomatoes. Plus, the kit comes with ten wooden label stakes that make it easy to tell your seeds apart.

Burpee Self-Watering Seed Starting System

Burpee's innovative Self-Watering Seed Starting System includes everything you need to grow strong, healthy seedlings. Each kit includes one large watering tray, two sixteen-cell planting trays with a self-watering mat and reservoir tray, and six plastic plant markers. Two Plant-o-Gram diagrams help you note what seeds you've sown in each extra large square cell.

The tray measures 10 in x 20 in with cells that measure 2.25 in x 2.25 in x 2 in., enough room to grow strong, healthy seedlings season after season.

Home Depot 12-Plant Germination Tray And Dome With Drainage Holes

With this 12-Plant Germination Tray and Dome Kit, you can build a mini greenhouse under grow lights, on a window sill, or sunny spot in your home. By creating the ideal environment, the cells promote healthy root development and speedy plant growth. Drainage holes make for easy watering, and a clear dome lid allows for adequate sunlight and lets you observe your plants as they grow. The kit includes six 5.8 in. x 7.3 in. bottom trays with twelve-hole inserts that can grow a total of 72 seedlings.

Bonivee Plant Starter Kit with Adjustable Humidity

While most trays use polyvinyl chloride (PVC), the Bonivee Plant Starter Kit uses a lower-density polypropylene (PP) material to better regulate temperature and humidity. Plus, each of the cells has a small drainage hole in the bottom that ensures proper drainage. By optimizing growing conditions, the trays help improve seed germination and survival rates.

Each of the 7 in. x 5.5 in. x 2 in. trays have twelve 1.5 in. x 1.5 in. cells that are the perfect size for starting flowers, vegetables, fruits, tomatoes, and other plants. The reusable plastic seed starter kit includes ten seed trays, ten watertight base trays, ten humidity domes, ten plant labels, and two small gardening tools.

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About the author

Bella has a Bachelors degree in interior design, is a master gardener. She designs nourishing outdoor & indoor spaces guided by the practice of Feng Shui.