Grow Vibrant Snapdragons from Seed: A Step-by-Step Guide

Have you considered growing gorgeous snapdragon flowers from seed in your garden? This guide walks you through the essential steps of sowing and germinating snapdragon seeds indoors, transplanting them into the garden, caring for them, and harvesting the gorgeous flowers throughout the growing season.

Snapdragons (antirrhinum majus) are excellent cut flowers known for their vivid colors and unique dragon-shaped blossoms. They’re one of the garden’s most productive early summer flowers. The more you cut, the more they bloom!

Starting Snapdragon seedlings indoors not only gives you a headstart on the gardening season but also offers a more controlled environment that optimizes the health and growth of your seedlings.

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Snapdragon Basics

The scientific name for snapdragons is Antirrhinum majus. Originating from the Mediterranean region, these annual plants or perennials (depending on the climate) thrive in cooler temperatures, making them ideal for late spring and fall gardens.

There are many types of snapdragons. They come in various colors, including red, pink, orange, yellow, purple, and white. They’re categorized by size into dwarf, medium, and tall varieties, ranging from 6 inches to 3 feet tall.

Snapdragons are easy to care for once they’re established. To thrive, they require well-drained soil, moderate watering, and a partially shaded or sunny location. These uniquely charming flowers attract pollinators like bees and butterflies to the garden.

Why You Should Grow Snapdragons from Seed

Growing snapdragons from seed indoors offers many benefits for gardeners, including those not available from buying young plants at the local garden center or nursery.

Cost-Effective

Starting snapdragons from seed is cost-effective. Seeds are significantly less expensive than purchasing seed starts, allowing you to grow many snapdragon plants at just a fraction of the cost.

More Varieties to Choose from

When you plant snapdragon seeds, you have a much wider variety of snapdragon types and colors that are unavailable as plants at the local nursery.

The taller varieties of snapdragons grown specifically for cut flowers are primarily available from seed. The smaller sizes are better for outdoor planters and window boxes.

Snapdragon Plants are More Protected Indoors

Growing snapdragons indoors from seed before transplanting them outside can produce more robust and resilient plants.

This is because they can be carefully monitored and protected from pests and harsh weather during the critical stages of growth.

When to Start Growing Snapdragons from Seed

To give your snapdragons the most extended blooming season possible, read the back of the seed packet for the best time to start sowing your snapdragon seeds indoors.

Knowing your USDA Plant Hardiness Zone is important before you sow your flower seeds. I start mine 8-10 weeks before the last frost in my area. Snapdragons germinate best in cooler temperatures.

The method of direct sowing in the garden after the last hard frost in spring also works because snapdragon plants can tolerate light frost.

Plant in loose, rich soil and full sunlight. Sprinkle snapdragon seeds lightly on the surface, then press them lightly into the soil.

Supplies for Growing Snapdragons from Seed

Steps for Sowing Snapdragon Seeds

Step 1: Choose a Clean Plant Container With Drainage Holes

Seed-starting containers should be clean and have drainage holes. You can read my blog post, Supplies Needed for Seed Starting, for several container options. I use cell trays and plastic pots for my seed containers.

If you’re reusing old plastic containers or trays, wash them thoroughly with a 1-part bleach/ 9-part water solution to help kill any lingering diseases or pathogens.

You can read more about how to clean your used containers in my post, Seed Starting 101 – Growing a Cut Flower Garden Series.

Step 2: Fill Containers with Moistened Seed Starter Mix

I recommend using a good-quality seed starting potting soil when sowing your snapdragon seeds. Good soil makes all the difference.

Before adding the seed starting mix to the container or seed trays, moisten them until thoroughly damp but not soaking wet.

Fill the cell trays or containers with the moistened seed starter mix. As you go, tap firmly against the table or shelf to ensure the soil settles and prevent air pockets in the containers.

Benefits of Using a Seed Starting Mix

Step 3: Label or Tag the Containers

Label the container of snapdragon seeds with the name of the variety of plants and the date planted. It’s easy to forget what you’ve planted in a particular container after only a few days.

Step 4: Sow Snapdragon Seeds

Because you’re working with such tiny seeds, I pick them up with a slightly damp toothpick and place them into the seed tray cell.

Snapdragon seeds won’t germinate without light, so don’t cover the seeds with soil.

Step 5: Bottom Water Your Seed Containers

Bottom watering is the most gentle and easy way to water your snapdragon seedlings. 

After sowing the snapdragon seeds, fill a drainage tray with about an inch of water and let the container sit in the tray to moisten the soil evenly. DO NOT leave the container in the tray full of water for over an hour.

It’s essential not to overhead water after you’ve placed the seeds in the container. You may wash the seeds away and have to start the process over again.

Watering from the bottom allows the roots to be watered thoroughly.

Step 6: Cover With a Humidity Dome Lid

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

Step 7: Pick the Right Location Indoors

Keep your seed starts in a light, bright space like a greenhouse or sunroom for best results.

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 daily and turn them off at night.

Step 8: Continue Watering

Check your containers every other day and bottom water when the soil looks and feels dry. Remove the tray of water once the soil surface is evenly moist.

Growing Snapdragons After the Seeds Have Germinated

Snapdragons are slower to germinate than most cut flowers. You should see growth within a couple of weeks.

Uncover the Container

Check the seed container daily. Remove the clear dome lid once the seeds have germinated, and the sprouts are visible.

Continue to Water When Needed

Check the seedlings daily to ensure the soil doesn’t dry out.

The very first leaves that appear on young plants are called cotyledons. Be sure to bottom water your seedlings until you see the first real leaves after the cotyledons.

Once those second sets of leaves appear, water with a gentle spray from a watering can or hose when needed, usually every 1-2 days.

Provide Good Air Circulation

Be sure the snapdragon seedlings have plenty of air circulation. A small fan near the seedlings will help prevent mold and encourage more vital, healthier plants.

Thin Snapdragon Seedlings if Needed

Once the snapdragon starts have two sets of true leaves, thin the seedlings to one plant per cell if needed.

Fertilize the Snapdragon Seedlings

Use water-soluble indoor plant fertilizer three to four weeks after planting the snapdragon seedlings. Be sure to mix the fertilizer to half-strength.

Pinching Your Snapdragons

Once a snapdragon plant is 4-6 inches tall and has at least three sets of leaves on each stalk, start pinching it back to encourage branching from the base of the plant for a bushier plant. This also helps to produce more blooms.

Snip off the central growing tips of the plant just above the leaf joints. Continue this throughout the growing season.

Preparing Garden Beds for Snapdragons

Preparing Garden Beds in Full Sun

Begin preparing garden beds by choosing a site that receives at least 6 to 8 hours of direct sunlight daily. This is crucial for developing strong roots, sturdy stems, and vibrant blooms.

Provide Nutrients

Amend the garden bed soil with organic matter, such as compost or aged manure, to improve its structure, fertility, and water retention before planting your young snapdragon seedlings.

Hardening Off Your Snapdragons

Now that you’ve grown your snapdragons from seed, hardening off your snapdragon seedlings is crucial in preparing them for harsher outdoor conditions. This process involves gradually exposing young plants to outdoor conditions for 7 to 10 days.

Start by placing your snapdragon seedlings in a sheltered, partially shaded area for a few hours daily. Avoid direct sunlight and strong winds, which could damage them.

Gradually increase the plant’s time outdoors daily, allowing them to experience more sunlight and the natural fluctuations of outdoor temperatures.

This gradual acclimatization helps to strengthen the seedlings’ cell structure and reduces the shock of moving from a controlled indoor environment to a variable outdoor climate.

Water the seedlings well during this period to prevent stress.

Transplanting Snapdragon Seedlings to the Garden

Snapdragons are pretty tolerant of the cold and can survive a light frost or two.

Once the plants have three sets of true leaves, you can transplant your seedlings into the garden a few weeks before the last frost date of the season.

After preparing the garden bed, create rows with proper spacing. This ensures that each snapdragon plant has enough room to grow and access sunlight, reducing competition and minimizing the risk of diseases like powdery mildew.

Add a layer of mulch after planting to help retain soil moisture, reduce weed competition, and keep root systems cooler under the intense sun.

Caring for Your Snapdragons

Your snapdragons will give you all the joy you need by following specific care needs throughout the growing season.

Protect Snapdragon Plants with Netting

Once these tall plants grow to about six inches high, they need extra support. Add a layer of soft mesh trellis netting to the beds to prevent the heavy snapdragon stems from toppling over in the rain and wind.

Watering

Snapdragons prefer consistent moisture levels, especially during the summer heat. Regular watering is crucial to maintain moist but not waterlogged soil.

The best time to water your cut flower garden is in the early morning, as this reduces evaporation and allows plant foliage to dry before nightfall.

Apply mulch around the plants to help retain soil moisture and reduce water evaporation.

Adjust your watering schedule based on the specific needs of your flower varieties and the current weather conditions.

Feeding Plants

Feeding your plants with a balanced, slow-release fertilizer at the beginning of the season can promote robust growth and abundant blooms.

Pest and Disease Control

Monitoring for pests and diseases and taking prompt action can also help maintain the health and beauty of your snapdragons.

Be sure to read more about organic and natural ways to manage pests.

Deadhead and Harvest Frequently

Deadheading spent flowers is another essential care step. It encourages the plants to produce new blooms, extends their flowering period, and grows bushier plants.

Harvesting Snapdragons

Timing and technique maximize snapdragons’ vase life when harvested during the growing season.

Save Snapdragon Seeds to Grow for Next Year’s Garden

As the flowering season starts to slow down, look for seed pods that form along the stem where the blooms once were.

These pods will mature and turn brown as the plant finishes its life cycle. This is when the seeds inside are ready for harvesting.

Carefully clip the p[ods from the plant and let them dry in a warm, well-ventilated area for about a week to ensure the seeds can be easily extracted.

Once dry, gently open the pods over a container to collect the seeds, which will be pretty small.

Store the seeds in a labeled, airtight container in a cool, dry place to maintain viability until the next planting season.

Common Mistakes Made When Growing Snapdragons from Seed

Growing snapdragons can sometimes have its challenges. Here are some common mistakes gardeners may make during a growing season:

Common Questions About Growing Snapdragons from Seed

How Long Do Snapdragons Take from Seed?

Snapdragons typically take 7 to 14 days to germinate fully under optimal conditions. The journey from sowing to seeing the first blooms can depend on growing conditions such as temperature, light, and care, but it generally follows a predictable timeline.

Once the seedlings emerge, the next few weeks will be spent developing a strong root system and foliage. This is when the seedlings must get proper light, water, and nutrient management for healthy growth.

Depending on the variety and the growing environment, snapdragons can begin flowering as early as 8 to 12 weeks after sowing.

The recommended start date for sowing seeds is about 8 to 10 weeks before the last expected frost date. This head start allows the plants to mature enough to be ready for transplanting outdoors once favorable conditions lead to an earlier bloom in the garden.

Do Snapdragons Come Back Every Year?

Snapdragons are often grown as annual plants but are technically perennials in USDA hardiness zones 7 through 11. Whether they come back each year depends on the climate and growing conditions in the garden.

Despite being grown as annuals in many areas, snapdragons tend to self-seed. The seeds dropped from last year’s plants can germinate and develop the following spring, giving the appearance that the plants are coming back each year.

To encourage self-seeding, leave some spent flowers on the plants at the end of the season to allow seeds to fall naturally to the ground.

Should I Start Snapdragon Seeds Indoors?

Starting snapdragon seeds indoors is effective, especially in regions with shorter growing seasons. Here are some reasons to consider sowing snapdragon seeds indoors:

Extended Growing Season

By starting seeds indoors, you can begin 8 to 10 weeks before your area’s expected frost date.

This head start allows your snapdragons to develop strong roots and foliage before being transplanted outside, ultimately leading to an earlier bloom in the garden.

Better Germination Rates

Snapdragon seeds can benefit from a controlled environment indoors, where temperature and moisture levels can be more consistently managed than outdoors.

This control over the growing environment can lead to higher germination rates and healthier seedlings.

Protection from Elements

Young snapdragon plants are delicate and vulnerable to harsh weather conditions, pests, and diseases.

Starting them indoors protects them during their most vulnerable stages, allowing them to grow stronger and more resilient before facing the outdoor environment.

Selectivity and Planning

Growing from seed indoors allows you to select from a wider variety of snapdragon types and colors than might be available at local nurseries as young plants.

It also gives you more control over your garden layout and design, as you can plan exactly where each plant will go once the seedlings are ready to be transplanted outdoors.

Cost-Effective

Starting plants from seeds is generally more cost-effective than purchasing young plants from a garden center.

A single packet of seeds can produce many seedlings at a fraction of the cost of buying the same number of grown plants.

Do Snapdragons Need Darkness to Germinate?

Snapdragons need light to germinate effectively. Unlike seeds that require darkness to kickstart germination, snapdragon seeds should be sown on the soil’s surface without being covered.

This exposure to light aids in triggering their germination process.

When starting snapdragon seeds indoors, gently press them into the surface of a moist, well-draining starting mix, ensuring they are in firm contact with the soil but not buried.

Will Snapdragons Bloom All Summer?

Snapdragons can bloom from late spring into early summer and, in some conditions, may continue to bloom throughout the summer and into fall. They do best in the cooler weather in spring and fall.

In cooler climates, snapdragons will bloom all summer long. But in milder climates, they sometimes bloom throughout the winter.

Their performance throughout the season depends on several factors, including the variety of snapdragons, the planting zone, and the care they receive.

Growing snapdragons from seed indoors allows gardeners to jump on the growing season, nurturing delicate seedlings in a controlled environment before introducing them to the garden.

This process extends the blooming period and allows for a broader selection of snapdragon varieties, tailoring the garden palette to personal preferences.

Attention to light requirements during germination, proper soil preparation, and the gradual acclimatization of seedlings are vital steps that ensure these charming snapdragon flowers reach their full potential. With the proper care, snapdragons can continuously display blooms from late spring into early fall.

If you have any questions or additional suggestions, please share them in the comments below. And be sure to share this blog post link with anyone who may find these gardening tips useful.

Until next time,

Happy Gardening!

I’m a self-taught hobby gardener. Everything I share on my blog is my opinion and what has worked for me.

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