How to Sow Snapdragon Seeds Indoors

Have you ever thought about growing good old-fashioned snapdragons in your garden? I’ll share my tips on sowing snapdragon seeds indoors, how to transplant them into the garden, and much more.

Snapdragons are one of my very favorite cut flowers in the garden. I first tried my hand at growing them from seed 3 years ago. After seeing these beauties in the Floret Flower Farm Cut Flower Garden book, I knew I needed them in my cottage garden.

These beautiful blooms produce gorgeous spikes and are one of the most productive early summer flowers in the garden. And my favorite part about snapdragons? The more you cut, the more they bloom!

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I’m a self-taught hobby gardener, not a Master Gardener. Everything I share with you on my blog is my personal opinion and things that have worked for me along the way.

Madame Butterfly Deep Red snapdragons — Madame Butterfly Dark Red Snapdragon | Credit: Floret Flowers

I’ve grown the same variety of snapdragons each year and just can’t get over how beautiful the Sherbet Toned Chantilly Mix colors are. But I’ve decided to up my game this season and will be trying the Madame Butterfly Dark Red Mix as well.

There’s a difference between the compact-sized snapdragons you buy at a garden store or nursery, and the flowers you grow from seeds like these. The smaller sizes are great to use in outdoor planters and window boxes, but these are specifically grown for cut flowers.

When to Plant Snapdragon Seeds

In order to give your snapdragons the longest blooming season possible, start sowing your snapdragon seeds indoors 8-10 weeks before the last frost in your area (I am in Zone 8B and have an average last frost date of April 18th). Snapdragons germinate best in cooler temperatures.

You can also sow the seeds directly in the garden after the last hard frost in spring because snapdragon plants can tolerate light frost. Plant in loose, rich soil and full sunlight. Sprinkle snapdragon seeds lightly on the surface of the soil, then press them lightly into the soil. Snapdragon seeds won’t germinate without light, so don’t cover the seeds. Water as needed to keep the soil evenly moist, but be careful not to overwater.

Supplies to Sow Seeds

Snapdragon Seeds (I buy mine at Floret Flower Farm)
Seed Starter Potting Mix
Containers
Drainage Tray
Plastic Dome Lid
Labels

Steps for Sowing Snapdragons

Step 1 – Fill Container with Soil

I would recommend using a good quality seed starting potting soil when sowing your snapdragon seeds. Good soil will make all the difference in the world. The soil should be moistened before adding it to the container.

BENEFITS TO USING A SEED STARTING MIX

Helps to germinate quickly
Holds the moisture
Allows the roots to penetrate down into the garden soil quickly.

You can make the mix go even further by filling the bottom half of the container with regular potting soil and then filling the rest of it with the seed starting mix, where the seeds are going to be placed.

Step 2 – Sowing the Seeds

Because the seeds are so small, I use a slightly damp toothpick and pick up 2 seeds, placing them into the seed tray cell. Sprinkle a light layer of seed starting soil or vermiculite to lightly cover the top.

seeds in cell containers and being bottom watered

Step 3 – Bottom Water

Bottom watering is the most gentle and easy way to water your snapdragon seedlings. Fill a drainage tray with about an inch of water and let the container sit in the tray to evenly moisten the soil. DO NOT leave the container in a tray full of water for more than an hour.

plastic dome lid covering snapdragon seeds

Step 4 – Cover

Cover your container with a plastic dome lid to increase the humidity and speed up the germination process.

Other Notes

Place in a cool greenhouse or in a bright window in the house. If you are sowing the seeds in a space with little light, place the plants 3-4 inches below fluorescent light bulbs or grow lights. Leave the lights on for 16 hours per day and turn them off at night.
Bottom heat isn’t necessary for snapdragon germination.
Be sure the seedlings have plenty of air circulation. A small fan placed near the seedlings will help prevent mold, and will also encourage stronger, healthier plants.
Water as needed to keep the potting mix evenly moist, but you never want to overwater and cause the soil to become oversaturated.

transplanted snapdragon seedlings in raised bed

Once the Sweet Peas Have Germinated

Take the plastic lid off the container once the seeds have germinated.

Snapdragons are pretty tolerant of the cold and can survive a light frost or two. You can transplant your seedlings into the garden a few weeks before the last frost date of the season, once the plants have 3 sets of true leaves.

Make sure to amend the garden beds with compost and organic fertilizer prior to planting. Space the snapdragon seedlings 9 inches apart.

Pinching

Once a snapdragon plant is 4-6 inches tall and has at least 3 sets of leaves on each stalk, start pinching it back to encourage the plant to actively branch from the base. This also helps to produce more blooms. Snip off the central growing tips just above leaf joints and continue this throughout the growing season.

Netting

Once the snapdragon plants grow to about six inches tall, add a layer of soft mesh trellis netting to the beds to keep heavy stems from toppling over in the rain and wind.

I hope this inspires you to grow some snapdragon seeds of your very own. I’d love to hear what you’ll be growing in your gardens this year. Be sure to leave me a comment.

You Don’t Need a Greenhouse

My friend Stacy at Bricks ‘n Blooms has a great blog post on everything you need to know about sowing seeds indoors. So for those of you that don’t have greenhouses, you can still grow flowers from seed.

How to Sow Snapdragon Seeds Indoors

When to Plant Snapdragon Seeds

Supplies to Sow Seeds