Depending on the growing region you live in, winter seed sowing allows you to start certain varieties of hardy flowers outdoors. In milder climates, directly sowing seeds is helpful if you don't have a lot of growing space inside. Some flowers actually thrive when sown outdoors, such as cold-hardy ones and those that require chilling to germinate. Keep in mind, however, that you can't sow seeds of any type when temperatures are below 10 degrees F. Read on to learn when to sow seeds for winter flowers and how to get started.
The Benefits of Winter Sowing
Sowing seeds in the winter has several upsides. Many cool-season flowers need an extended chilling period to create a natural stratification process that initiates sprouting. The cold conditions that seeds experience when sown in winter help them break dormancy and encourage germination.
Winter sowing can also provide earlier blooms than indoor seed starting. The seeds will germinate when the weather is just warm enough, allowing for a longer growing period and healthy plants that flower slightly earlier than transplants. Direct sowing also provides natural light, which encourages faster, healthier growth than artificial lights. Starting seeds indoors also requires a period of hardening off plants before transplanting them outdoors. Direct sowing avoids that process.
Choosing Winter Flowers
Many popular flowers grow only when mild weather arrives, but cold spells are essential for other types. These cold-tolerant plants are typically perennials that flower early in the season and fare well in cool growing conditions. Once the seeds are planted in the ground, the alternating mild and cold spells, plus frequent rain or snow, trigger germination. Without these natural rhythms of winter, the seeds may not germinate.
When you're selecting flowers for winter sowing, look for seeds labeled with terms like "cold tolerant," "cold hardy," "cool season," "sow in autumn" or "sow in early spring" for successful planting. Here are a few winter-sown flowers to try in your garden:
- Anise hyssop (or Agastache) - While your senses are nourished all summer by the rich purple flower spikes and their spicy fragrance, bees and other pollinators feed on their nectar.
- Butterfly weed - Hummingbirds as well as butterflies flock to the orange, white, or purple blossoms of this summer bloomer.
- Columbine - For this spring perennial, you can choose from different colors, including shades of red, pink, purple, blue, yellow or white.
- Gayfeather (or blazing star) - When summer hits its peak, the deep-purple flower spikes stand tall in your perennial border.
- Pansy - One of the most cold-hardy annual flowers, pansies emerge as soon as the soil thaws in spring.
- Poppy - The fluttery blooms of this spring perennial come in vivid red, pink, orange, or purple.
- Viola - The bright little blossoms of violas hold up through the chilliest spring conditions.
Deciding When to Sow Seeds for Winter Flowers
The right time to plant seeds depends on the flower species and your garden growing zone. For example, in milder winter regions, like zones 6 and 7, winter hardy annuals like 'Tutti Frutti' snapdragons and 'Johnny-Jump Up' violas can be sown by the end of September or the beginning of October for a bloom starting in February. In warmer zones, like zones 8 and 9, wait to sow seeds as late as November and December. Colder zones require early fall sowing or none at all, as there's a strong chance they won't survive. Check your own growing zone against these general winter sowing parameters:
- Zones 1-2: Not suitable
- Zones 3-4: Early August or not at all
- Zone 5: August or September
- Zones 6-7: September or October
- Zone 8: October or November
- Zones 9-11: December
Growing Winter Flowers From Seeds
You can plant seeds in winter in two ways: directly sowing the seeds in the ground, or starting them in a covered container or cold frame. Using a container protects the seeds from elements and animals, and it prevents excess moisture, which may dislodge seeds. However, seeds sown in containers may require transplanting, which may be stressful for the seedlings.
If planting in a container, make sure it's clean, has proper drainage, and won't crack over the winter. Fill the container with a damp potting mix and sow your seeds. Like indoor seed starting, a clear plastic cover over the soil can retain warmth and moisture and help seeds germinate. Once the seedlings sprout, remove the cover. When the seedlings are large enough to handle, they can be placed into your flower border to continue growing.
While the seeds are sprouting and the seedlings are tender, you can give them a little extra protection with the Burpee Exclusive Adjustable Frost Protection Kit. A plastic milk jug with the bottom cut off or a clear plastic food container may also work to shelter seeds and sprouts.
With the right seeds and growing conditions, winter-sown flowers provide an early jump on your garden, giving you a longer blooming period to enjoy.
To learn more about sowing seeds successfully, check out Burpee's guides to direct sowing.
Depending on the growing region you live in, winter seed sowing allows you to start certain varieties of hardy flowers outdoors. In milder climates, directly sowing seeds is helpful if you don't have a lot of growing space inside. Some flowers actually thrive when sown outdoors, such as cold-hardy ones and those that require colder temperatures to germinate. However, it's essential to keep in mind that you can't sow seeds in the coldest temperatures, like anything below 10 degrees Fahrenheit. Keep reading to learn when to sow seeds for winter flowers and how to get started.
Understanding the Benefits of Winter Sowing
Sowing seeds in the winter has several upsides. Many cool season flowers need an extended cold period to create a natural stratification process. The cold conditions seeds experience when sown in winter help break dormancy and encourage germination.
Winter sowing can also provide earlier blooms than indoor seed starting. The seeds will germinate when the weather is just warm enough, allowing for a longer growing period and healthy plants that flower slightly earlier than transplants. Direct sowing also prevents suffering from too little light, a common problem with seeds sown indoors. Starting seeds indoors also requires a period of hardening off plants before transplanting them outdoors. Direct sowing avoids having to go through this process.
Choosing Winter Flowers
Although many flowers prefer planting when mild weather arrives, some prefer to experience cold spells before germinating. These cold-tolerant plants are typically perennials that flower early in the season and like cool growing conditions, such as the 'Brilliant Red' (Oriental) poppies. Once planted in the ground, the seeds are subject to alternating mild and cold spells, plus frequent rain or snow. Without these natural rhythms of winter, the seeds are reluctant to germinate.
Seeds from hardy annual varieties, like viola and pansy, can also be sown in winter to get a good start early in spring. When you're selecting flowers for winter sowing, look for seeds labeled with terms like "cold tolerant," "cold hardy," "cool season," "sow in autumn" or "sow in early spring" for successful planting.
Deciding When to Sow Seeds for Winter Flowers
Deciding when to sow seeds depends on the seeds themselves and your own garden growing zone. For example, in milder winter regions, like zones 6 and 7, winter hardy annuals, like 'Tutti Frutti' snapdragons and 'Johnny-Jump Up' violas, can be sown by the end of September or the beginning of October for a bloom starting in February. In warmer zones, like zones 8 and 9, you'll want to wait to sow seeds as late as November and December. Colder zones require early fall sowing or none at all, as there's a strong chance they won't survive. Check your own growing zone against these general winter sow parameters:
Zones 1-2: Not suitable
Zones 3-4: Early August or not at all
Zone 5: August or September
Zones 6-7: September or October
Zone 8: October or November
Zones 9-11: December
Growing Winter Flowers From Seeds
You can sow seeds in winter in two ways: directly sowing the seeds in the ground, or sowing them in a covered container or cold frame. Using a container protects the seeds from elements and animals, and it prevents excess moisture, which may dislodge seeds. However, seeds sown directly won't require transplanting, which may be stressful for the seedlings.
If planting in a container, make sure it's clean, has proper drainage and won't crack over the winter. Fill the container with a damp potting mix and sow your seeds. Like indoor seed starting, a clear plastic cover over the soil can retain warmth and moisture and help seeds germinate. Once the seedlings sprout, you can remove the cover. When the seedlings are large enough to handle, they can be placed into your flower border to continue growing.
You can also use a milk jug or clear plastic food container to protect seeds and create a similar greenhouse effect. Punch a few holes in the bottom for drainage and one or two on the top for ventilation on sunny spring days. Cut into the container three-quarters of the way around the middle so the lid can open to allow for ventilation and close when the seeds need protection. Fill the lower part of the container with damp potting mix and sow your seeds. Place the container outside, but not too close to buildings that may radiate excess heat.
With the right seeds and growing conditions, winter-sown flowers provide an early jump on your garden, giving you a longer blooming period to enjoy.
To learn more about sowing seeds successfully, check out Burpee's guides to direct sowing.
Written by Shahrzad Warkentin
Shahrzad Warkentin is a writer and seasoned gardener, with over 12 years of experience. Besides her own home garden, she helps manage her kids' school garden.