How to Plant Frozen Seeds?

The GardenSpring |

Long-term seed storage is a useful strategy, whether you are growing native plants or have purchased more seeds than you can use. By saving the seeds of the plants you grow, you can save money and feel good about being self-sufficient.

So in this article, you’ll discover how to plant frozen seeds. Let’s start.

Long-term seed storage

There are several methods for long-term seed storage, depending on how long you want to keep the seeds. If you only want to store extra seeds for next year’s planting, you can pack them in plastic bags or store them in a cabinet or kitchen drawer.

However, not all seeds will germinate next year. This is a less favorable outcome if you have saved native seeds or rely on saved seeds to feed yourself each year.

If you want to store seed for longer than a year, or if you want to achieve a higher germination rate, you should store it in the refrigerator or freezer. Both methods work, but freezing seeds is usually the best option for longer storage, as long as it’s done properly.

Freezers versus refrigerators

Seed banks store their seed in freezers because they offer the best long-term storage. They can store rare seeds for many years and must ensure the safety and viability of the seed.

However, seed banks also have special equipment for freezing and storing seeds that the average household does not have. For this reason, some people believe that freezing and storing seeds is out of the question for the average gardener, but this is incorrect.

Freezing seeds at home will not harm most seeds. Rather, some seeds need to be frozen or at least refrigerated before germination. The main advantage for home gardeners who want to store seeds in the freezer is that the freezer is opened much less frequently than the refrigerator.

When stored in the refrigerator, seeds can be exposed to fluctuations in temperature and humidity. Dry seeds have a longer survival time, and fluctuations in humidity and temperature can kill seeds.

Prepare seeds for storage

After collecting seeds, it is important to dry them. Moisture can cause mold, and freezing can cause ice crystals to form inside the seeds. Colorado State University recommends spreading the seeds outdoors to dry them thoroughly.

Drying in an oven or microwave can cause the seeds to become too dry. Check for dryness by cracking the seeds. If it breaks easily, it is dry. If it bends or crumbles, it is not dry enough.

The dried seeds can be placed in an envelope labeled with the name of the plant and the year the seeds were collected. It is advisable to add a note about the growing conditions of the plant and anything else you would like to record from the previous season.

The envelope should then be placed in a sealable seed storage container. Seeds in plastic bags are generally not recommended, as they are not as well protected as in a closed seed container.

Do peppers grow from seed?

Like humans, seeds are more active in certain temperature zones. In warmer areas, seeds should be sown outdoors when nighttime temperatures are around 60 degrees Fahrenheit. Monk’s pepper seeds take up to four months to germinate, while the seeds of other types of peppers take up to one month.

Super Hots also require temperatures above 85 degrees Celsius to germinate. Some seeds do not germinate initially. Stored in an airtight container with desiccant and in the refrigerator or freezer, they are viable for 25 years, but at room temperature, seed vigor declines after two to five years. Discard floating seeds.

Which seeds should be protected from the cold?

Seeds are the birth of new life for plants. but how to plant frozen seeds? To maximize seed germination and the life of new plants in home gardens and backyards, it is often necessary to mimic the conditions under which seeds germinate in nature.

Cryo treatment is one of the most common methods used to break seed dormancy and promote germination.


Like shrub seeds, most tree seeds require cold treatment before germination. Cooperative Extension’s Redbud, Dogwood, Crabapple, and Southern Magnolia seeds require several months to break dormancy and stimulate germination.

North Carolina Extension has found that cold stratification can accelerate seed germination in pines.

Flowering perennials

Seeds of herbaceous plants that grow in temperate zones require maturation at low temperatures before germination. This can be accomplished by placing the seeds in moist sand in the refrigerator for 1-3 months.

Among the most common perennials in the home, the garden is aconite, gentian, and echinacea, and the well-known purple cornflower and new varieties are also popular perennials of this type.


An environmentally friendly way to collect wildflowers for home cultivation is “seed collecting.” Many wildflower seeds need to mature under false winter conditions at low temperatures before they can germinate.

Columbine, bleeding heart, false Solomon’s seal, bloodroot, and jackfruit are wildflower seeds that are slow or impossible to germinate without months of cold treatment.

Photo by Gelgas Airlangga on pixels

Are seeds killed by freezing?

seed banks store rare, exotic, and heirloom seeds in refrigerators or cold rooms to ensure the survival and future of certain plant varieties. If you garden at home, you probably don’t have a cold room in your garden shed, nor do you need to store thousands of seeds for decades. However,

if stored properly, they can be kept in the refrigerator or freezer. Improper freezing can kill seeds, but some are not so finicky. In fact, many seeds of wildflowers, trees, and shrubs require a period of low temperature (ripening) before they can germinate.

In colder climates, plants such as milkweed, echinacea, walnut, and cycads drop their seeds in the fall and remain dormant under snow all winter. When temperatures and humidity rise in the spring, these seeds germinate.

However, without the preceding cold dormancy period, these seeds would not germinate. This ripening period can be easily reproduced in the freezer. The key to success is storing dry seeds in airtight containers at consistently low temperatures.

Freezing wet seeds can cause them to crack or split, so they should be thoroughly dried before freezing. Dried seeds should be stored in airtight containers to absorb moisture and prevent harmful moisture from sticking to them.

Seeds stored in the refrigerator should be stored in the back of the refrigerator to reduce temperature fluctuations caused by opening and closing the door. Seeds can be stored in the freezer at a more stable temperature than in the refrigerator.

For every 1% increase in humidity, the shelf life of the seed is halved. Similarly, if the temperature increases by 10°C (-12°C), the shelf life of the seed can be reduced by half.


Hill, C. (2020, September 3). What Seeds Need Cold Treatment? Garden Guides.

Turner, D. L. (2021, November 12). Pet-Safe Fertilizers: Benefits, Brands & Alternatives. Home Guides | SF Gate.

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