37 Seeds That Require Cold Stratification To Germinate

Have you experienced difficulty in the past getting certain seeds to germinate? They might need cold stratification. In this article, gardening expert Melissa Strauss talks about some common plants that require cold stratification for germination.

On a brown table, a man's hand carefully plants tiny seeds atop a snowy layer covering the soil in a small pot. Nearby, several small brown pots and a tiny shovel are arranged for his gardening work.


Have you ever tried to grow lavender from seeds with little success and lots of frustration? Hopefully, I am not the only one. Before I learned about cold stratification, I had no idea that these seeds require a period of cold weather to initiate the germination process. Still, it makes sense, considering the temperature shifts in their native environment.

Lavender isn’t the only plant that requires cold stratification before planting. There are actually quite a lot of plants that have this requirement. Some of them are easier to grow from cuttings or divisions, but if you truly want to grow your plants from seed, cold stratification is something you want to be armed with the knowledge of first

What is Cold Stratification

A close-up of a transparent container holds dark, rich soil where tender snapdragon seedlings flourish. The gardener inspects the seeds after the winter stratification process to see if they have successfully germinated.
Cold stratification expedites germination or permits the growth of cold-dependent plants in warmer environments.

Many plants native to cooler climates require a period of cold weather to break their dormancy and initiate the germination process. Cold stratification is a way of mimicking that process so that germination can be expedited, or plants that require this cold weather to germinate can also be grown in warmer climates. 

Not all seeds need the same conditions to encourage germination. Some need warm, moist weather, while others need a cold period. Some have more complicated needs, requiring a combination of different factors to break their dormancy. 

Stratification happens naturally over the winter. The fluctuations in the weather trigger both the dormancy and the emergence from that dormancy, so the seeds know when the season is right to grow. Some seed packets will indicate if varieties require stratification, but others may not.

How To Do It

gainst a backdrop of dark, fertile soil, a man diligently places brown tulip bulbs. Next to him, a wooden crate is filled with bulbs awaiting planting. Below, an assortment of gardening tools is ready for digging and planting.
Initiate the stratification process early to give ample time for exposure to required cold temperatures.

The easiest way to cold-stratify your seeds in a moderate to cool climate is to plant your seeds in the fall. By planting in the fall, they will experience natural cold stratification without the gardener having to do much work. If you live in a warm climate, you’ll need to carry out the process artificially.

If the species you are sowing are native or you have a similar climate to their native range, the process is simple. All you need to do is know which seeds require stratification, and you can simply plant them at the right time, usually in the fall. This mimics the natural self-seeding process of these plants. 

Flowers tend to drop seed in the fall before entering dormancy or dying off for the winter. The objective is to create a similar environment to the one they would naturally experience. 

It can take one to three months to cold-stratify seeds, so consider that timeline when you choose a time to begin. If you intend to plant in the spring, you’ll want to time it so they are adequately exposed to cold temperatures. 

Artificial cold-stratification is typically done using a refrigerator at a temperature between 33°-40°F. It is done wet or dry, depending on the type of seed. In general, if the seed grows naturally in an arid climate, it must be kept dry for this process, and vice versa. 

Seeds that Need Cold Stratification

Without further ado, I’d like to share some information on common seeds that require cold stratification. Details on how to have the greatest success with these plants through the germination process are included. 


A close-up of Arnica yellow flowers reveals their bright, sun-kissed petals and delicate, slender stems. The green leaves provide a vibrant backdrop to these cheerful blooms, accentuating their natural beauty.
Remember that arnica relies on light for germination.
botanical-name botanical name Arnica montana
sun-requirements sun requirements Full sun
height height 1’-2’
hardiness-zones hardiness zones 4-9

Arnica seeds should be soaked for four hours before stratification. They need cool, moist stratification for about eight weeks before they are ready to germinate.

They also need light to germinate, so do not cover them with soil. Just gently press them into the seed starting mix or potting soil.


A close-up of an Artichoke plant showcases a magnificent, large green flower on a sturdy stem. The broad, serrated leaves surrounding the flower create a striking contrast, adding to the plant's allure.
Be cautious not to expose these seeds to freezing temperatures.
botanical-name botanical name Cynara cardunculus var. scolymus
sun-requirements sun requirements Full sun
height height 3’-4’
hardiness-zones hardiness zones 7-11

If you are planning to grow your own artichokes this season, they will need a bit of assistance. Artichoke seeds need just a brief period of cold stratification to germinate. They can go in the fridge for about two weeks.

Don’t let these seeds freeze, as they are frost-sensitive. Start your artichokes indoors in seed trays, and keep them around 60°-70°F for best germination results.

Balloon Flower

A close-up of a Balloon Flower plant captures the enchanting purple blooms, resembling inflated balloons, on dainty stems. The green leaves offer a harmonious backdrop, enhancing the delicate charm of this captivating flower.
For optimal growth, perform cold stratification and scarification before planting balloon flower seeds.
botanical-name botanical name Platycodon grandiflorus
sun-requirements sun requirements Full sun to partial shade
height height 1’-2’
hardiness-zones hardiness zones 3-8

Balloon flower grows best if cold stratification and scarification take place before planting. These seeds like to be exposed to the sun for germination and can take a while to sprout.

They don’t handle transplanting well, so direct sowing is best. Expect your balloon flowers to germinate when the soil temperature reaches about 60°F.

Black-eyed Susan

A close-up of Black-eyed Susan flowers displays their vibrant golden petals with dark centers, perched on slender stems. The lush, serrated leaves below the flowers provide a lush and verdant foundation for these striking blossoms.
Rudbeckia is a beloved choice due to its robust nature and constant blooming.
botanical-name botanical name Rudbeckia
sun-requirements sun requirements Full sun
height height 4’-5’
hardiness-zones hardiness zones 4-9

Rudbeckia are a favorite in my garden. They are sturdy, consistent bloomers, and the bees adore them. Cold stratify your black-eyed Susan seeds for about one to three months and start six to eight weeks before your last expected frost. Transplant your seedlings once the average temperature reaches 65°F.

Butterfly Bush

A close-up of the Butterfly Bush showcases its dark purple flowers clustered on slender stems. The lance-shaped leaves add to the elegance of the plant, offering a perfect complement to the vivid, soft blooms.
To germinate, the seeds of the butterfly bush need a brief period of cool, damp conditions.
botanical-name botanical name Buddleja
sun-requirements sun requirements Full sun
height height 5’-8’
hardiness-zones hardiness zones 5-10

Butterfly bush is happy to grow in warm climates, but the seeds do need a brief period of cool, moist temperatures to germinate. Give them about four weeks of cold stratification and then sow indoors eight to 10 weeks before your last expected frost. They need light to germinate, so don’t cover them with soil. Just press them in lightly.

Note: Butterfly bush is invasive in some regions. Please check with your local extension office before planting and deadhead blooms before they set seed.


A close-up of Catmint flowers highlights their enchanting light purple blossoms, adorning slender, graceful stems. The delicate beauty of these flowers is truly a sight to behold in any garden.
A little cold stratification goes a long way for catmint seeds.
botanical-name botanical name Nepeta
sun-requirements sun requirements Full sun to partial shade
height height 6”-12”
hardiness-zones hardiness zones 3-8

Catmint doesn’t need very much cold stratification, but a little goes a long way. Pop these seeds in the freezer for a day, then soak them in water for 12-24 hours before planting. Seeds can be started indoors six weeks before the last expected frost or direct sown once temperatures rise to 50°F.


A close-up of Chamomile reveals its charming white flowers with sunny yellow centers perched on slender, delicate stems. These dainty flowers exude an air of tranquility, making them a lovely addition to any garden.
A mix of cold and warm stratification is necessary to germinate chamomile seeds successfully.
botanical-name botanical name Matricaria chamomilla
sun-requirements sun requirements Full sun to partial shade
height height 2’
hardiness-zones hardiness zones 3-9

Chamomile seeds need a combination of cold and warm stratification to germinate. Keep them warm and moist for two weeks before cold stratifying for about four to six weeks.

The ideal temperature for chamomile seeds to stratify is between 33°-35°F. Start seeds indoors three to four weeks before your last expected frost, or direct sow when the soil reaches 45°F.

Chinese Lantern

A close-up of a Chinese Lantern plant showcases its striking orange lantern pods dangling from intricate branches. The green leaves provide a lush backdrop, making the plant a visual delight in any garden.
Cold stratification, though not mandatory, enhances the germination rate of Chinese lantern seeds.
botanical-name botanical name Physalis alkekengi
sun-requirements sun requirements Full sun to partial shade
height height 1’-2’
hardiness-zones hardiness zones 3-9

While it is not required, cold stratifying your Chinese lantern seeds will improve their germination rate. Give them two weeks of cold temperatures, and then soak your seeds overnight before planting. You can directly sow these seeds or transplant seedlings after the threat of frost has passed.


A close-up of Coneflower displays its vibrant pink flowers with striking orange centers, standing tall on sturdy stems. In the background, lush green leaves create a vibrant tapestry, framing these stunning blooms beautifully.
For optimal coneflower seed germination, provide a brief cold spell.
botanical-name botanical name Echinacea
sun-requirements sun requirements Full sun
height height 2’-4’
hardiness-zones hardiness zones 4-9

Coneflower seeds germinate best when given a brief period of cool weather. Without this, you may only get a germination rate of about 30%.

Plant your seeds in a moist potting mix and cover. Then, place them in the fridge for about four weeks. Keep the soil moist during this period. 

Evening Primrose

A close-up of the Evening Primrose plant highlights its bright yellow flowers that seem to glow in the sun's embrace. The green leaves, with their graceful shape, serve as a lovely contrast to the radiant blossoms.
Remember to sow evening primrose seeds on the soil’s surface since they require light to germinate.
botanical-name botanical name Oenothera biennis
sun-requirements sun requirements Full sun
height height 3’-5’
hardiness-zones hardiness zones 4-9

Evening primrose seeds need a brief period of cold stratification to improve germination. Give these seeds moist stratification for three to four days for best results.

You can stratify these seeds in their potting mix. Sow your seeds on top of the soil, as these seeds need light to germinate. 

False Sunflower

A close-up of False Sunflower plants reveals bright, yellow petals with brown centers, standing tall on sturdy branches. Dark green leaves provide a lush backdrop to the vibrant flowers.
Stratification is essential for false sunflowers, necessitating a month of cold and moist storage.
botanical-name botanical name Heliopsis helianthoides
sun-requirements sun requirements Full sun
height height 3’-6’
hardiness-zones hardiness zones 4-9

For false sunflowers, stratification is required. These seeds should be kept cold and moist for about one month.

The seeds germinate at 65°-70°F, so they should be planted indoors or outdoors when the weather warms up. They take 21-28 days to germinate, so these require a bit of patience, as well. 


A close-up of a Fuschia plant showcases striking hanging red flowers on slender stalks. The leaves, deep green and serrated, add to the plant's lush beauty.
Fuchsia seeds may display variable germination times, averaging 30 days.
botanical-name botanical name Fuschia
sun-requirements sun requirements Partial shade
height height 1’-3’
hardiness-zones hardiness zones 9-11

Even though they are warm climate plants, fuchsias need some cold stratification. It is important to not keep them at or below freezing, as they are not frost tolerant. These seeds need about one month of cold stratification before planting.

Fuchsia seeds can be unpredictable and take 30 days to germinate on average. Soaking them for 24 hours before planting will speed up the germination time. 


A close-up of a Goldenrod plant features a profusion of tiny yellow flowers, creating a burst of sunshine. The lance-shaped leaves serve as the perfect background, accentuating the golden blooms.
The low-maintenance goldenrod plant thrives in a wide range of climates.
botanical-name botanical name Solidago
sun-requirements sun requirements Full sun
height height 2’-5’
hardiness-zones hardiness zones 2-8

Goldenrod is easy to grow and naturalizes well in most climates. Cold stratification is necessary for these seeds and should be carried out for 60 days.

The seeds should be lightly pressed into the top of the soil, as they need light to germinate. Germination will take two to three weeks if the soil is kept at or near 70°F.

Hardy Hibiscus

A close-up of a large pink Hardy Hibiscus highlights a stunning, intricate flower with delicate pink petals and a prominent stamen. Surrounding green leaves create a vivid contrast to the vivid bloom.
Hardy hibiscus seeds need a minimum of 60-90 days of cold temperatures.
botanical-name botanical name Hibiscus
sun-requirements sun requirements Full sun
height height up to 25’
hardiness-zones hardiness zones 4-9

Unlike their tropical cousins, hardy hibiscus seeds need cold stratification. Hibiscus seeds need at least 60-90 days of cold temperatures to germinate.

After cold stratification, lightly scarify the seeds and soak them in water overnight. The seeds and plants are moisture and humidity lovers, so keep them moist and covered. They only take about 3-5 days to germinate. 


A close-up of Heather plants displays clusters of dainty pink flowers atop straight stalks. The needle-like leaves, deep green and tightly packed, complement the delicate blooms.
When planting, gently press heather seeds into the soil without covering them.
botanical-name botanical name Calluna vulgaris
sun-requirements sun requirements Full sun
height height 1’-2’
hardiness-zones hardiness zones 5-8

Heather seeds need cold and moist stratification for maximum germination. Six weeks in the fridge will prep your heather seeds for germination, which takes 28-35 days.

These seeds need a soil temperature between 55°-70°F for germination and exposure to light, so lightly press them into the soil, but do not cover them. 


A close-up of a Hens-and-chicks plant reveals its succulent pointed leaves, which form a rosette. Each leaf is uniquely textured and patterned, enhancing the charm of this desert plant.
Remember that hens and chicks are succulents that can’t handle excessive moisture.
botanical-name botanical name Sempervivum
sun-requirements sun requirements Partial shade
height height 4”-8”
hardiness-zones hardiness zones 3-8

Hens-and-chicks, as well as all other varieties of sempervivum, require cold stratification of their seeds. Two to three weeks in the fridge will do the trick.

These seeds need light to germinate and a soil temperature of 70°F. These plants don’t need much moisture as they are succulent, so avoid waterlogging your seedlings.


A close-up of a hops plant reveals its distinct flowers or seeds clustered in a unique hanging form. These stand out distinctly against the vine's serrated, lush green leaves.
Be patient with hops since they take 30-40 days to sprout.
botanical-name botanical name Humulus lupulus
sun-requirements sun requirements Full sun
height height 15’-20’
hardiness-zones hardiness zones 4-8

If you’re thinking about brewing your own beer, you’ll definitely need some hops. Hops seeds should be moist cold stratified as close to 41°F for three months before planting.

These seeds require some patience, as they take 30-40 days to germinate. However, once they sprout, they grow very quickly, up to an entire foot in one day!


A close-up of Hollyhock plants displays long, elegant stems adorned with a variety of pink, white, and red flowers. The petals form a colorful display against the backdrop of lush, green leaves.
Hollyhocks share common germination and care requirements with hardy hibiscuses.
botanical-name botanical name Alcea
sun-requirements sun requirements Full sun
height height 6’-8’
hardiness-zones hardiness zones 4-8

Hollyhocks are closely related to hardy hibiscuses, and they have similar needs in terms of germination and care. While they may germinate without stratification, your germination rate will be significantly better with it.

Plant these seeds when the soil temperature is between 59°-58°F. They should sprout within two weeks. 

Anise Hyssop

A close-up of Anise Hyssop exhibits slender stalks with light purple flowers, reminiscent of lavender. The leaves which are soft green surround the blooms.
You should subject anise hyssop seeds to one month of cold, moist stratification.
botanical-name botanical name Agastache foeniculum
sun-requirements sun requirements Full sun to partial shade
height height 3’
hardiness-zones hardiness zones 4-8

Anise hyssop is a favorite in the pollinator garden and spreads prolifically in its native areas. If you are planting it from seed, the seeds will require a brief cold stratification to improve germination results. Cold, moist stratification for one month before planting will produce the best germination rate, which takes one to four weeks.


A close-up of an Ironweed plant captures vivid pink flowers in various stages of bloom on sturdy branches. The green leaves, broad and toothed, frame the striking floral display.
Cold stratification is a valuable method for the challenging task of growing Ironweed from seed.
botanical-name botanical name Vernoia
sun-requirements sun requirements Full sun
height height up to 8’
hardiness-zones hardiness zones 4-9

Ironweed is another popular plant in the pollinator garden. It can be difficult to grow from seeds, but cold stratification drastically raises the germination rate.

Ironweed seeds need to stay moist through the winter and stratification process. Stratification should last for six to eight weeks. Seeds need a soil temperature of 50°F or higher to germinate. 

Joe Pye Weed

A close-up of a Joe Pye Weed plant reveals vibrant pink flowers clustering on its branches, drawing pollinators near. Its lush green leaves, veined and serrated, provide a beautiful backdrop for these blooms.
Avoid planting Joe Pye weed seeds deeply, and place your trays in a sunny location.
botanical-name botanical name Eutrochium purpureum
sun-requirements sun requirements Full sun
height height 6’
hardiness-zones hardiness zones 4-8

Joe Pye weed is a great pollinator feeder and easy to grow. These seeds need 30-60 days of cold stratification to germinate.

They also need plenty of light for germination, so don’t plant deeply, and set your trays in a sunny spot. It takes Joe Pye weed seeds about four weeks to germinate in the soil at 70°F.


A close-up of Larkspur plant showcases a profusion of delicate flowers on tall, elegant stalks. The blossoms exhibit a stunning array of colors, including shades of blue and lavender, creating a captivating and colorful display.
These showy flower seeds can be started indoors or planted directly in the soil.
botanical-name botanical name Delphinium
sun-requirements sun requirements Full sun
height height 3’-4’
hardiness-zones hardiness zones 4-8

Larkspur doesn’t need much in terms of cold stratification. However, two weeks in the fridge will significantly increase your germination rate. You can place them in a damp paper towel inside a plastic sandwich bag and put them right into the fridge.

Larkspur seeds can be planted as soon as the soil is workable and can be started indoors ahead of time. These seeds need darkness for germination, so plant them ¼” deep, and your larkspurs should pop their heads up in two to three weeks. 


A close-up of a Lavender plant. The small, purple flowers adorn the plant's woody stalks, creating a tranquil scene.
The ideal chill time for lavender seeds is three to four weeks in the refrigerator.
botanical-name botanical name Lavandula
sun-requirements sun requirements Full sun
height height up to 4’
hardiness-zones hardiness zones 5-9

If you love lavender like I do but have difficulty getting your seeds to sprout, there is good news ahead! Lavender seeds require cold stratification. Three to four weeks in the fridge is the right amount of time to prep these seeds for germination.

After cold stratifying your lavender seeds, you can start them indoors about 10-12 weeks before your last frost date or wait until the ground thaws and sow them directly.


A close-up of a Lobelia plant highlights brilliant blue flowers contrasted by vibrant green, youthful leaves. The vivid blossoms pop against the foliage, making this plant a striking addition to any garden.
Due to their minuscule size, initiating lobelia growth indoors is advisable.
botanical-name botanical name Lobelia
sun-requirements sun requirements Full sun to partial shade
height height 4”-18”
hardiness-zones hardiness zones 9-11

Lobelia doesn’t technically have to be cold-stratified. They are warm-climate plants that grow as perennials in zones 9 to 11. However, your germination rate will increase if you give your lobelia seeds three to four weeks of cold temperatures.

Don’t allow these seeds to freeze; after stratification, bring them to 70°F to germinate. These seeds are very tiny, so it’s best to start them indoors. 


A close-up of Lupine plants displays a bouquet of flowers perched on long, graceful stems. These lupines come in an array of colors, including vibrant shades of orange, yellow, violet, and pink, adding vibrancy to the landscape.
Expect lupine seeds to sprout within two to three weeks once they warm up.
botanical-name botanical name Lupinus
sun-requirements sun requirements Full sun
height height 1’-4’
hardiness-zones hardiness zones 4-9

Lupine seeds have a hard outer coating that needs special treatment. Soak your lupine seeds in water overnight before you begin your cold stratification.

Scarify your seeds with fine grit sandpaper, and then cold stratify for about one week. Germinate your lupine seeds in soil with a temperature between 65°-75°F; they should sprout in two to three weeks

Marsh Marigold

A close-up of a Marsh Marigold plant showcases sunny yellow flowers nestling amid lush, green leaves. The contrast between the vibrant blooms and verdant foliage creates a picturesque scene.
These lovely marsh marigolds need a period of cold weather to stimulate them.
botanical-name botanical name Caltha palustris
sun-requirements sun requirements Full sun to partial shade
height height 8”-24”
hardiness-zones hardiness zones 3-7

Marsh marigolds are so bright and pretty in the garden. These pretty plants have seeds that require some cold weather to wake them up, as well.

In fact, this is one seed you can leave in the fridge all winter or for three months anyway. To germinate, sprinkle the seeds on top of moist potting soil and give them five to 10 days to sprout. 


A close-up of a Milkweed plant reveals clusters of orange flowers branching out from its dark green leaves. The vivid blossoms stand out against the backdrop of the plant's rich foliage, attracting pollinators.
Typically, most milkweed varieties will sprout within 10-15 days once properly stratified.
botanical-name botanical name Botanical Name: Asclepias
sun-requirements sun requirements Full sun
height height up to 6’
hardiness-zones hardiness zones 4-9

You probably know milkweed for its use by monarch butterflies as a larval food, as well as a nectar plant. These butterflies lay their eggs exclusively on this genus of plants, and more than 70 species are native to the United States.

Cold-stratify your milkweed seeds for three to six weeks with some moisture before planting them. Most types of milkweed have a germination time of 10-15 days.


A close-up of a Penstemon plant highlights pink, bell-shaped flowers perched gracefully on slender stems. The plant's foliage, with its distinctive leaves, adds depth and texture to the composition.
Penstemons boast impressive flower power, making them delightful plants.
botanical-name botanical name Penstemon
sun-requirements sun requirements Full sun
height height 12”-24”
hardiness-zones hardiness zones 4-9

Penstemons, or beardtongues, are wonderful plants with tons of flower power. Their seeds need cold stratification for about five weeks just before planting.

Keep them moist and at just above-freezing temperatures. Penstemon requires patience, as the seeds can take six to eight weeks to germinate after they are planted.

Perennial Sweet Pea

A close-up of Perennial Sweet Pea captures the gentle charm of its light pink flowers on slender stalks. Against the blurred background of lush greenery, these blooms exude a sense of serenity and natural beauty.
Keep sweet pea seeds moist and refrigerate for approximately five weeks.
botanical-name botanical name Lathyrus latifolius
sun-requirements sun requirements Full sun to partial shade
height height 6’-9’
hardiness-zones hardiness zones 4-8

Perennial sweet pea seeds need to be cold stratified at cold, but not freezing temperatures. They should be kept moist and can be refrigerated for about five weeks.

The seeds will germinate in soil that ranges between 55°-65°F, so as soon as your soil warms, pop these seeds in the ground and give them plenty of water. They should germinate in as few as ten or as many as 28 days. 

This plant can become invasive, as it spreads rapidly via seeds and rhizomes. Keep it in a container and remove spent blooms to prevent spread.

Pincushion Flower

A close-up of a Pincushion Flower plant with delicate light lavender flowers standing tall on slender stalks. The soft, blurred background enhances the elegance of these blossoms, adding a touch of grace to the garden.
Scabiosa’s stunning appearance in floral arrangements and long vase life make these flowers ideal for cut flower gardens.
botanical-name botanical name Scabiosa
sun-requirements sun requirements Full sun
height height 8”-12”
hardiness-zones hardiness zones 3-8

These flowers look wonderful in a floral arrangement and have a long vase life, so they work very well in a cut flower garden. They will germinate without cold stratification, but your germination rate will be increased with just a little time spent in the fridge.

Two weeks is all that is needed, and then they should be sown indoors about six to eight weeks before the average last frost date. 

Prairie Coneflower

A close-up of Prairie Coneflower plants reveals vibrant yellow flowers with dark, bulging centers. Their slender stems stretch gracefully, supporting lush, green leaves that add to their natural beauty.
For optimal germination, prairie coneflowers prefer soil temperatures ranging from 68° to 80°F in a sunny spot.
botanical-name botanical name Ratibida
sun-requirements sun requirements Full sun
height height 1’-3’
hardiness-zones hardiness zones 4-9

Prairie coneflower is different from most of our seeds in that it needs stratification that is cold and dry. Eight weeks is just about right regarding how long to cold stratify these seeds.

In terms of germination, these seeds germinate best in soil temperatures between 68°-80°F in a sunny location. Germination only takes two to three days for Prairie Coneflowers.

Prairie Violet

A close-up of the Prairie Violet, the delicate lavender flower structure captivates with its intricate petals and dainty appearance. Surrounding it, the leaves provide a lush backdrop, enhancing its charm.
A soil temperature of 80°F is ideal for the germination of prairie violets.
botanical-name botanical name Viola pedatifida
sun-requirements sun requirements Full sun to partial shade
height height 3”-6”
hardiness-zones hardiness zones 3-8

Prairie violets are sun-loving and drought-tolerant, two characteristics uncommon to the genus. Their seeds need about 60 days of cold stratification in a moist environment. A minimum of 30 days is the least these seeds should be stratified for.

The seeds should be sown on top of the soil, as they need light to germinate. 80°F is a good soil temperature for prairie violets to germinate. 


A close-up of the Sedum plant showcases clusters of pink flowers elegantly blooming on branches. The leaves, a rich green hue, create a harmonious contrast with the blossoms.
Once the danger of frost has subsided, you can sow sedum seeds both indoors and outdoors.
botanical-name botanical name Sedum
sun-requirements sun requirements Full sun to partial shade
height height 1’-3’
hardiness-zones hardiness zones 3-11

Many types of succulents need cold stratification to germinate, including plants in the Sedum genus. Sedum seeds should be cold-stratified for four to five weeks to increase the germination rate.

The seeds can be sown indoors or outdoors after the threat of frost has passed. They need exposure to light for germination, so don’t cover them with soil. Just sprinkle them on top. 

Shooting Star

A close-up of the Shooting Star plant reveals the graceful, light purple flowers that adorn tall stalks, resembling celestial bursts. Their slender and elongated structure adds a touch of elegance to the garden.
Place shooting star seeds on the soil surface and gently press them in for proper germination.
botanical-name botanical name Primula sect. dodecatheon
sun-requirements sun requirements Partial shade
height height 1’-2’
hardiness-zones hardiness zones 4-8

This pretty wildflower blooms for a brief time in the spring. Their seeds prefer cold, moist stratification, which should be carried out for 30-60 days.

The seeds can be sown directly in the ground, but wait until the threat of frost has passed. They need light for germination, so lay them on top of the soil and press lightly. Don’t cover them with soil. 


A close-up of the Soapwort plant highlights the soft white flowers adorned with light purple markings, while nearby buds hint at the promise of future blooms. The sturdy stem provides a robust foundation for these delicate blossoms.
These seeds benefit from a month of cold stratification and thrive in a moist setting.
botanical-name botanical name Saponaria
sun-requirements sun requirements Full sun to partial shade
height height 6”-36”
hardiness-zones hardiness zones 3-9

Soapwort seeds need to be cold-stratified for about one month, but also like a moist environment. After cold stratification, place these seeds on top of the potting mix and in a sunny spot, as they need light for germination.

Germination should take place in 10-21 days. They germinate best with a soil temperature near 70°F.

St. Johns Wort

A close-up of the St. John's Wort plant showcases the intricate structure of its yellow flowers, featuring vibrant centers that shine like tiny suns. The leaves provide a verdant contrast to this botanical masterpiece.
Typically, it takes about two weeks for St. John’s wort seeds to initiate their growth.
botanical-name botanical name Hypericum perforatum
sun-requirements sun requirements Full sun to partial shade
height height 2’-4’
hardiness-zones hardiness zones 3-9

You may know this plant from its use as a homeopathic remedy, but it is also a very pretty plant with attractive yellow flowers. St. John’s wort seeds need to spend three or four weeks in moist, cold stratification to germinate.

They also need light to germinate and prefer a soil temperature around 70°F. It takes roughly two weeks for these seeds to germinate. 

Wild Geranium

A close-up of a Wild Geranium plant featuring the blue, velvety softness of its flowers. The green leaves provide a lush backdrop, creating a natural contrast that pleases the eye.
Cultivating this North American woodland native wildflower is a delightful choice.
botanical-name botanical name Geranium maculatum
sun-requirements sun requirements Partial shade to full shade
height height 12”-28”
hardiness-zones hardiness zones 3-8

This woodland native of North America is a great wildflower to cultivate. It is easy to propagate but not invasive and produces pretty pink flowers.

Wild geranium seeds need moist, cold stratification for 60 days for ideal germination success. Sow seeds in soil that is around 70°F, keeping the soil moist during germination. These seeds can take two to three months to germinate, so patience is required. 

Final Thoughts

The simplest way to grow plants that require cold stratification is to plant them in the fall and allow nature to do what it does best. However, that is not always possible or convenient. Fortunately, the process of artificial cold stratification is a simple one. Armed with the knowledge of which seeds need it and for how long, we can grow many of the plants that may have eluded us in the past. 

A close-up reveals multiple lavender lupine flowers with delicate petals on long, slender stems. The vibrant blooms contrast beautifully with the lush green leaves that surround them.


Are Lupines Annual, Biennial, or Perennial Plants?

Interested in planting some lupines but confused about how they grow? Want to know more about those spiky purple flowers that drift through the meadow each spring? In this article, certified master gardener Liz Jaros examines the varying life cycles within the lupine genus and clears up some confusion surrounding this unusual plant.

october perennials


15 Perennials You Can Plant This October

Thinking of putting some perennials in the ground this October? There are plenty of perennials you can plant, depending on your hardiness zone. In this article, gardening expert Jill Drago looks at her favorite perennial plants to settle into your garden in the month of October.

sowing seeds outdoors


How to Direct Sow Seeds Outdoors at the Proper Depth

Are you direct sowing seeds into your garden this season? Planting your seeds at the proper depth is critical for strong and healthy plants. In this article, gardening expert and former organic farmer Logan Hailey shares exactly how deep you need to plant your seeds when direct sowing into the ground.