38 Seeds You Should Freeze Before Planting for Better Germination

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Discover 38 types of seeds you should freeze before planting to ensure better germination!

There are certain seeds in the plant kingdom that you should freeze to avoid a poor germination rate after planting and if you are wondering why, read below!

Check out here the simple seed germination tips to grow every seed

Why Should You Do this?

It is a process that seeds undergo to mimic the winter for breaking their dormancy to kickstart germination. It’s especially crucial for plants native to cooler climates.

Artificially, gardeners can replicate this process using refrigeration. Please note that the stratification periods vary in duration; some seeds may require a few weeks to several months of cold exposure.

Best seeds for gardening that grow quickly in just 5 days

Seeds to Freeze Before Planting

1. Hops

Hops Seeds You Should Freeze Before Planting

Duration: 4-8 weeks

Once done, you can plant the seeds indoors or outdoors when the weather warms up a bit.

2. Viburnum

Viburnum seeds stratified

Duration: 4-12 weeks

Cold stratification helps in ensuring the successful germination of Viburnum seeds. Studies have shown that stratified seeds generally exhibit higher germination rates.

3. Arnica

Arnica seeds on table Seeds You Should Freeze Before Planting

Duration: 8 weeks

After the freezing process, soaking the seeds for 4 hours before stratification (lightly scratching the seed coat) can be helpful to rehydrate them and improve germination rates.

How to grow Arnica montana

4. Black-Eyed Susan

Black-Eyed Susan pot in garden Seeds You Should Freeze Before Planting

Duration: 4-6 weeks

If you start this 6 to 8 weeks before the last frost, it will be a good strategy for outdoor planting.

5. Redbud

Redbud seeds stratification Seeds You Should Freeze Before Planting

Duration: 5 to 8 weeks

Different Redbud species may have slightly different dormancy requirements. Some, like Eastern Redbud, may require longer stratification periods (up to 8 weeks).

6. Rose

Duration: Around 6-8 weeks (some may not require)

After stratification, sow the seeds in damp sand, vermiculite, or a mixture of perlite and peat moss.

Look at the essential rose care tips for bigger flowers

7. Pear

Pear soak the seeds in water

Duration: 8-12 weeks

After the cold treatment, sow them outdoors at temperatures above 40 °F (4 °C).

8. Catmint

Catmint in metal pot

Duration: A day in the freezer followed by 12-24 hours soaking in water.

If planting seeds indoors, starting 6 weeks before the last frost is recommended for optimal development before transplanting outdoors

9. Artichokes

Artichokes in garden

Duration: 2-4 weeks

Artichokes are perennials that naturally flower in their second year. A cold period can trick them into thinking they’ve experienced winter.

Check out the best types of  Artichoke plant varieties

10. Anise Hyssop

Anise Hyssop from seed in garden

Duration: 4 weeks

You can also sow the seeds directly into the garden in early fall, allowing them to experience cold stratification during the winter months.

11. False Sunflower

False Sunflower plant near wall

Duration: About 4 weeks

False Sunflower seeds can also naturally be sown in winter. Planting can be done indoors or outdoors, both.

12. Goldenrod

Goldenrod plant in blue pot

Duration: 8 weeks

You can also achieve this process by sowing the seeds outdoors in late fall or early spring, allowing the seeds to be naturally exposed to prolonged cold.

13. Heather

Heather seed-stratification

Duration: 6 weeks

After this cold treatment, the seeds take about 1 to 2 months to germinate.

Learn here how to grow heather in pots

14. Larkspur

Larkspur seeds germination

Duration: 1-2 weeks

After cold stratification, start planting seeds indoors about eight weeks before the last frost of spring or directly in flower beds in early summer.

15. Lavender

Lavender seeds for freezing ziplock bag

Duration: 4-6 weeks

Place the lavender seeds in potting soil in a ziplock plastic bag and refrigerate it. Also, note that these seeds might be tricky to germinate.

Check out here everything about growing French lavender

16. Soapwort

Soapwort Seeds You Should Freeze Before Planting

Duration: About 2-3 weeks

When sowing the seeds (Spring is ideal), provide them full to light shade. Also, note that this plant is best suited to Zones 5 to 7.

17. Swamp Milkweed

Swamp Milkweed Seeds You Should Freeze Before Planting

Duration: 4-8 weeks

You can plant them indoors in small pots, seed trays, or outdoors after the frost danger is passed.

18. Peach

Peach Seeds You Should Freeze Before Planting

Duration: 8-10 weeks

Peach seeds must be chilled at an ideal temperature between 35-50°F.

19. Strawberry

Strawberry potted plant

Duration: 3-4 weeks

Strawberry seeds need freezing for successful germination. Plant them in a seed starting mix for best results.

Check out here growing strawberries from strawberry scraps

20. Eastern White Pine

Eastern White Pine plant in garden

Duration: 4-12 weeks

Place the seed in a freezer bag with lightly moistened perlite for two to three months in the refrigerator. Sow them in pots 1/4 inch deep and cover lightly.

21. Raspberry

Raspberry in black pot

Duration: At least 5 weeks

Plant the seeds in a spot where they get dappled sunlight, and the germination would take a few weeks.

Check out how to grow raspberries in pots

22. Penstemon

penstemon plant in terracotta pot

Duration: About 4-5 weeks

Ensure you provide full sun or partial shade, dry to moisture medium, and well-draining soil.

23. Prairie Coneflower

Duration: 7-8 weeks

Plant it in the fall, but if you are planning in spring, then the seeds will require vernalization (prolonged cold period to promote flowering).

24. Prairie Violet

Prairie Violet germination

Duration: About 7-8 weeks

Avoid covering the seeds with a growing medium, as they need light for a successful germination.

25. Blueberries

Blueberry planter in garden

Duration: 8-12 weeks

Before freezing, you must remove the pulp from the seeds. They take 6-8 weeks for germination.

Learn here how to grow blueberries in a container

26. Shooting Star

Shooting Star Seeds You Should Freeze Before Planting

Duration: 4-8 weeks

The seeds may take up to 5-6 years to reach the flowering phase. It also depends on the light and growing conditions.

27. Marsh Marigold

Marsh Marigold in yard

Duration: 8-12 weeks

The seeds can be planted after the cold treatment directly on the ground. Germination takes place in 5-10 days.

Here is the list of marigold flowers that are worth growing

28. St. John’s Wort

St. John's Wort plant in terracotta pot

Duration: 3-4 weeks

They prefer well-draining soil and typically take about 2-3 weeks to germinate.

29. Apple

Apple plant seeds ermination in pot

Duration: 2-3 weeks

After the cold period, sow the seeds in an area where they receive direct sunlight.

Here are the popular sweet apple varieties

30. Serviceberry

Serviceberry seed germination

Duration:  12 weeks

After stratifying the seeds, sow them and maintain a temperature between 70 and 77F (21 and 25C).

31. Oregon Grape

Oregon Grape in garden

Duration: 8-12 weeks

Sow the seeds into the ground before the first frost. They may take 3-5 weeks to germinate.

32. Wild Columbine

Wild Columbine seeds germination

Duration: 6-8 weeks

Cold stratification aids in breaking the dormancy of these seeds, promoting more uniform germination.

33. Butterfly Bush

Buddleja white pot in garden

Duration: About 4 weeks

You can sow the seeds indoors 8 to 10 weeks before the last frost.

Should I cut my butterfly bush to the ground, find out

34. Winterberry


Duration: 7-8 weeks

It is a slow-growing shrub, and its seeds require 1-2 months of warmth before the cold treatment.

35. Sugar Maple

Sugar Maple seeds
Jones Homestead

Duration: 10-12 weeks

After the process, it would be a good idea to start the seeds in a tray using a seed starting mix. Once germinated, plant them in the garden.

Check out sugar maple tree growing guide

36. River Birch

River Birch gerrmination

Duration: 4-12 weeks

After the process, place the seeds in pots filled with potting soil in a place where they receive bright sunlight.

37. Hawthorn

Hawthorn plant near fence

Duration: 12-17 weeks

Sow stratified seeds directly into the ground or a container after choosing an apt location with plenty of sunlight.

38. Magnolia

Magnolia seedling

Duration: 7-9 weeks

Plant the seeds and cover them with about 1/4 inch of soil until the seedling emerges.

Learn here how to grow Magnolia Alba easily 

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