15 Seed Starting Supplies to Make the Process Easier

Is the weather cold and gloomy outside, with your garden hibernating under a blanket of snow? Are you dreaming of summer veggies and browsing garden catalogs to help quell the winter blues?

There’s nothing better for blustery weather and SAD attitudes than the pleasure of seed starting. While it may be too early to start most seeds in January, it’s never too early to plan, order seeds, and gather seed starting supplies so you’ll be ready to get your hands in the soil for some indoor garden therapy!

Whether you’re an experienced seed grower or among the millions of new gardeners starting seeds for the first time, we’ve compiled a list of ideal seed starting supplies to make your seedy adventure a pleasure that yields gorgeous, healthy, strong plants.

Some seeds grow best sown directly in the garden in spring when the temperatures rise and the soil warms. However, other seeds, like tomatoes, peppers, and eggplant, need a head start indoors to produce strong plants ready for the gardening season.

Seed packets offer a wealth of information. Take a look at the instructions on the seed packet for information about where and how to sow the seeds. Learn more from Ask The Experts…about #SeedFacts.

Before you begin your seed starting journey, keep in mind that plants need adequate light, controlled temperatures, water, and good airflow. To maintain your sanity, you’ll want to avoid starting seeds on your dining room table, unless you’re unbothered by mess. Pick a spot for a comfortable workstation where you have access to electricity, consistently warm temperatures, and mess doesn’t matter. (You WILL spill seed starting mix and water, so unless you’re lucky enough to own a heated greenhouse, find a corner of a heated basement or craft room for your seed starting activities.)

Order your seeds

Once you find your ideal space, start gathering supplies. Make a list of your favorite veggies, fruit, and flowers, and order seeds—pronto. With the surge of interest in gardening, seeds are in high demand, and you want to ensure that your favorite tomatoes or zinnias aren’t sold out. Visit our National Garden Bureau seed company members to find your favorite varieties and don’t forget to try something new! Why buy the usual varieties, start something new and have fun!

Once you’ve placed your order, it’s time to gather supplies. Some companies offer seed starting kits with many of the supplies you need packaged together. But many supplies can be found at home.

Starting seeds indoors gives plants a great start. Using biodegradable pots is a good way to avoid disturbing roots when transitioning seedlings to the garden. (Photo courtesy NGB member Johnny’s Seeds.)

Seed Starting Kits includes many of the supplies you need to get started

Seed Starting Kit includes many of the supplies you need to get started. (Photo courtesy NGB member Botanical Interests.)

Our top 15 recommendations for seeds starting supplies include:

Seed starting chart for timing
Seed starting trays with humidity domes
Biodegradable pots
Soilless seed starting mix
Bucket
Soil scoop
Heat mat with thermostat
Grow light station: light fixtures with adjustable chains and full-spectrum bulbs
Timer
Extension cord
Plant tags
Marker or grease pencil
Spray bottle
Sandpaper or nail file
Small container with lid

1. Seed Starting Chart

You’ve selected your seeds, and they’re beckoning to you, begging for attention. The snow is swirling outside, and you’re eager for some garden therapy. Is it time to start sowing seeds?

WAIT.

Starting seeds too early can be just as detrimental as starting them too late. It can be a challenge to keep a too-tall tomato healthy inside until May or June. But how do you know when to start sowing seeds, so the plants are ready at just the right time for your garden?

Seed packets offer a wealth of information. You’ll find information about days until germination, as well as days to maturity, along with light needs and other great tips. However, if you’re starting a lot of seeds, it can be tricky to keep track of the different germination times, making it confusing to know when to start growing.

Fortunately, you can find an excellent resource online with Johnny’s Seeds Seed-Starting Date Calculator. First, find your expected last spring frost date. Then, plug the date into the calculator. The calculator tells when to start seeds indoors, as well as when to transplant outside, broken out by crop. This tool helps ensure you start your seeds at just the right time.

2. Seed Starting Trays with Humidity Domes

Of course, if you plan to start seeds indoors, you’ll need something to contain those plants-to-be. While you’ll find dozens of ideas for upcycled seed-starting containers on Pinterest, make sure that whatever you choose to use for growing seedlings offers plenty of depth for adequate growing mix. You want big, strong roots, and they can’t develop in a tiny bit of growing medium or space. Make sure the container provides drainage to avoid root rot.

Seed germination cell trays make the perfect option for growing lots of plants in a limited space. You can find propagation trays in a wide range of cell counts, from 50 cells to 200. Use small cells for plants like lettuce, which will be transplanted quickly, and larger cells for plants that grow deep root systems. These rigid, reusable trays allow you to grow seeds with similar requirements in one tray—for instance, plants like tomatoes and peppers prefer bottom heat and good light. By inserting a tag with the variety name into each row or cell, you can grow several plant varieties in one tray, while avoiding variety mix-up.

Seedling Grower Starter Kit from National Garden Bureau Member

Johnny’s Seeds Seedling Grower Starter Kit combines many elements you need for seed starting. Propagation trays are available in many different cell sizes. (Photo courtesy NGB member Johnny’s Seeds)

Park Seed Bio Dome 40 Cell - National Garden Bureau

Park Seed’s Bio-Dome Seed-Starting System is crafted for optimal seed growth with vents to promote essential airflow. (Photo courtesy NGB member Park Seeds)

Use small plant tags or cut larger ones in half when adding variety tags to cell trays. Small tags allow the humidity dome to fit on top of the tray.

Because cell trays provide drainage holes, insert the cell tray into a leak proof tray to protect furniture and avoid water spillage. Leak-proof trays are also great for bottom watering delicate seedlings. Add water to the bottom tray, allow the seedlings to soak up the water for an hour or two, then dispense of the standing water.

One of the most important tips for growing seeds is to keep the growing medium moist but not soggy. A humidity dome placed over the cell tray helps preserve moisture, keeping the seeds happy. Remove the dome as the seedlings grow to ensure good air circulation.

3. Biodegradable Pots

Some seedlings, like sunflowers, spinach, and corn, prefer direct sowing, as their roots dislike disturbance. However, by starting seeds in biodegradable pots, you can jump-start growing your favorite plants, making sure they’re ready for the garden season. Biodegradable pots come in a wide range of options, from rectangular, small, multi-cell strips to six-inch round pots. If using biodegradable cells, place them in a leak-proof tray with a humidity dome to help preserve moisture. Regardless of the option you choose, make sure to place a tray underneath the biodegradable pots, as water passes easily through them.

Once the weather warms and your seedling has grown big and strong, dig a hole and plant the entire container in the garden, container, or raised bed. The plant’s roots will grow through the biodegradable pot into the surrounding soil, and the pot will decompose throughout the season.

Biodegradable pots make transitioning seedlings to the garden a breeze - National Garden Bureau

Biodegradable pots, like those offered by Johnny’s Seeds, make transitioning seedlings to the garden a breeze. ( Photo courtesy NGB member Johnny’s Seeds)

Botanical Interests Paper Pot Family - National Garden Bureau

Botanical Interests’ biodegradable recycled paper pots decompose when planted in garden beds. ( Photo courtesy NGB member Botanical Interests)

Make sure to harden off your seedlings before planting them in the garden. “Hardening off” means to acclimate your indoor-grown seedlings to outdoor conditions. Slowly introduce your seedlings to the great outdoors for about 10 days, placing them in sun for an hour or so on the first day, gradually adding more time each day. Hardening off helps avoid sun-scalded leaves.

4. Soilless Seed Starting Mix

Skip the garden soil and invest in soilless seed starting mix to give your seeds the best start. When growing seeds indoors, a soilless mix offers a finer, lighter choice than typical garden potting soil, making it easier for young roots to navigate and grow in the medium. The main reason to use a sterilized seed starting mix is health: mold and fungi issues can kill delicate seedlings, ruining your hard work and plant joy. Sterilized seed starting mixes contain no contaminants or pathogens, creating a healthy, hospitable home for your young seedlings.

Until your seedling develops true leaves (the first leaves you’ll see are cotyledon, or “seed leaves”), the plant draws its nutrients from the seed and doesn’t require additional fertilization. Once it forms true leaves, it’s time to pot up the seedling into nutrient-rich potting soil.

5. Medium-Sized Container with Lid

If you have a container already, wash it out well and sterilize it with a 10 percent bleach/90 percent water solution. Rinse well. Add the seed starting mix to the container, pour in a bit of water, and mix to thoroughly moisten the medium. Using a container makes it easy to scoop the pre-moistened mix into the trays, and then pop on the lid to store leftover seed starting mix.

6. Soil Scoop

Fill the propagation trays or seed starting containers with seed starting mix using a deep scoop, then use your hands to level the soil and tamp it into each cell. Make sure each cell is filled fully so the seed has plenty of medium for establishing roots.

7. Heat Mat with Thermostat

Some seeds, like tomatoes and peppers, need warm soil to germinate well. Adding a heat mat with a thermostat to set the ideal soil temperature helps ensure even, speedy germination. Cold soil can inhibit germination, and cold, wet soil may even cause seeds to rot. Using the combination of a heat mat and thermostat allows you to control soil temperature for better germination.

Heat mats with thermostats for seed starting - National Garden Bureau

Heat mats with thermostats, like the Agritape Heat Mat from Harris Seeds, provide controlled bottom heat to help with germination. (Photo courtesy NGB member Harris Seeds.)

Hoss Germination Mat (100 Watt) - National Garden Bureau

Maintaining a constant soil temperature when germinating seeds or propagating plants like tomatoes and peppers is easier with a heat mat like 100 Watt Germination Mat from Hoss Tools. (Photo courtesy NGB member Hoss Tools.)

8. Grow Light Station with Full Spectrum Bulbs and Adjustable Chains

Some seeds need light to germinate, while others, like pansies, prefer dark. However, as soon as seeds begin growing, they all need an adequate light source. When growing indoors, set up a light stand with full-spectrum bulbs that mimic the sun’s rays. Ideally, place the lights about two inches above the seedlings. It’s important that the lights’ height is adjustable to “grow” with the plants.

You’ll find many versions of grow lights available, from multi-tier stands to smaller single-light stations perfect for starting your favorite seeds.

High-quality LED lights, like those from Happy Leaf LED, mimic natural daylight for strong, healthy plants. (Photo courtesy NGB member Happy Leaf LED)

A unit with shelves and grow lights makes the perfect seed starting station. National Garden Bureau

A unit with shelves and grow lights makes the perfect seed starting station. (Photo courtesy NGB member Harris Seeds.)

9. Timer

To make your life easy, plug the grow lights into a timer. Seedlings need between 12 to 18 hours of light each day. With a timer, the lights will turn on and off at the same time each day. It’s a nice time-saver to make sure your seedlings consistently receive proper light or try a grow light station with a timer built in.

10. Extension Cord and Power Strip

Heat mats, grow lights, thermostat—with so many electrical elements, it’s handy to add an extension cord and a power strip to your supply list.

11. Plant Tags

You may think you’ll remember exactly what seeds you planted in which tray, but in a week—you won’t. Add the name of each plant variety to a plant tag and stick it into the individual cell or row. You’ll be happy you did!

12. Marker or Grease Pencil

Some pens and pencils fade quickly on plant tags. Variety names written with a permanent marker or grease pencil last longer when exposed to soil, water, and light, making sure you can identify your seedling. Or use a Waterproof Marker.

13. Spray Bottle

Seeds need careful watering, especially before they germinate and when they first sprout. A spray bottle filled with water allows you to easily keep the seed starting mix moist without disturbing the seed or newly formed roots. The fine mist also helps avoid overwatering.

14. Sandpaper or Nail File

Some seeds require extra encouragement to germinate, especially thick, hard-coated seeds like nasturtium. In nature, an animal might eat the seed, and its digestive juices would break down the seed coating before it passes. It’s easy to mimic nature through “scarification”—nicking the outer seed coating with a nail file or sandpaper to allow the seed to absorb water and begin germination. Be careful, though—only nick a bit of the outer coating without damaging the interior.

15. Small Container with Lid

Along with some seeds needing scarification, others, like some perennials, require a chilling period before germination called “stratification.” All you need is a small container filled with seed starting mix. Moisten the mix, add the seeds, pop on the cover, and place in the refrigerator. Stratification requirements vary by species, so check your seed packet for more information. Whether the seeds need two weeks or two months, make sure the mix never dries out during stratification.

You’re Ready!

You’ve gathered your seed supplies, set up your seed starting station, organized your seeds according to start times…now what? If it’s still a bit too early to start your seeds, consider joining a seed swap. Seed swaps are fun ways to try new seed varieties. Instead of buying ten packets of tomato seeds for ten different varieties, partner with some friends or neighbors to swap seeds so that you all can enjoy the pleasure of growing new varieties.

Are you starting your seeds indoors this year?

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1 comment. Leave new

David Arnold

January 13, 2023 5:18 pm

Seed Tapes are easy to use and are the perfect route to seed sowing success!!
https://ngb.org/2022/03/16/why-use-seed-tapes-discs/