Freezing seeds before planting is something that can be done with certain varieties of plants, although it is not necessary for all plants. When seeds are frozen, it slows down the aging process. By essentially “stopping time” for the seed, the plant can remain viable for a much longer period of time.
A controlled cold storage environment at temperatures between 0 and -18°C can extend the lifespan of certain seeds from just a few years to several years. Depending on the type of seed, they may last as long as 10 years!
When you freeze seeds, it is important to store them in airtight containers so that moisture doesn’t build up, which could damage the seed. It is also important to thoroughly dry the seeds before placing them in the freezer, as moisture can cause the seeds to freeze and thaw several times, leading to sudden temperature changes which can damage the seed’s viability.
When the time comes to plant your frozen seed, you should take steps to make sure that you don’t dry the seed out. For example, you could store the seed in a damp cloth to help maintain moisture until the seed is planted in moist soil.
Additionally, planting in a moist environment will help warm up the frozen seed as it begins to germinate. With the proper care, frozen seeds can offer gardeners with the ability to store certain varieties of seeds for a much longer period of time than would otherwise be possible.
What seeds should not be frozen?
It’s not advisable to freeze most types of seed. Certain types, such as liquid-filled or soft-skinned seeds, such as watermelon and squash, as well as certain types of nuts, will not survive freezing temperatures.
Some seeds, such as fennel, star anise, and sesame, should be stored in airtight containers in the refrigerator to prevent them from spoiling. Freeze-dried seeds, such as pumpkin and sunflower, can be successfully frozen, but should be stored in a vacuum-sealed, airtight container for optimal storage.
When in doubt about which seeds to freeze, it’s best to consult a seed supplier, as they’ll have advice on which seeds can be frozen and how best to store them.
How long should seeds be out of freezer before planting?
Seeds should be out of the freezer for at least a day before planting to allow the seeds to adjust to air-temperature and full exposure to moisture. During this time, the seeds should also be kept in a cool and dry environment, away from direct sunlight.
Allowing the seeds to be out of the freezer also helps to prevent shock from the sudden change in temperature, as a rapidly changing environment can be very stressful for seeds. This “transition phase” is also important for determining if the seed is viable.
Moisten a paper towel and place the seeds on it. After 12-24 hours, inspect the seeds to see if they are beginning to swell or show signs of life. If no signs of life are visible, discard the seeds.
Are seeds ruined if they freeze?
No, most seeds are not ruined if they freeze. In fact, some types of seeds actually benefit from being exposed to temperatures below freezing, as cold temperatures can help break the dormancy period and stimulate growth.
However, some seeds may be more susceptible to damage from freezing if they are exposed to too much moisture or if they are not stored properly. Generally speaking, it is best to store seeds in a cool, dry place prior to planting, as this will keep them dry and protect them from extreme temperatures.
In addition, some seeds may benefit from a period of cold stratification, which involves storing them in temperatures between 32-41°F for several weeks. This can help break the dormancy period and allow for better germination.
Can you grow plants from frozen seeds?
In short, yes, frozen seeds can successfully germinate and grow into healthy plants. Some conditions around freezing and extended storage of seeds will influence the health of the germinated seeds and the plants they produce.
It is important to understand the best practices to ensure a successful yield of healthy plants.
When properly frozen, seeds can survive in a dormant state for years, and remain viable for germination. Though storage of seeds at moderate temperatures below freezing or above 60 degrees Fahrenheit can reduce the viability of the seeds to very low levels in a relatively short period of time.
Prolonged storage at very low temperatures or greater than 100 degrees Fahrenheit can render the seeds non-viable.
For best results, it is advisable to store seeds at a temperature of 0 degrees Fahrenheit or below. However, keeping the seeds in the freezer section of most home refrigerators will provide a viable storage temperature that allows for the storage of seed stocks for many years.
To give seeds their best chance of success when freezing, select only healthy, mature seed and ensure the seed is thoroughly dry prior to freezing. This helps to reduce the risk of damage to the seed coat.
To freeze, store the seeds in an airtight container such as a jar, plastic bag or container and place in the freezer.
When ready to plant frozen seed, bring the seeds out of the freezer and allow to thaw naturally without subjecting them to dramatic changes in temperature or humidity. From there, you can use the common germination methods in accordance with the seed variety planting instructions.
Generally, enough moisture, a temperature of 60-75°F and darkness are necessary conditions for germination to occur.
Overall, frozen seeds have the potential to germinate and successfully grow into healthy plants, as long as specific guidelines are followed and the seed quality is maintained. It is important to ensure the seeds are properly frozen, stored and thawed prior to planting to maximize their potential for healthy germination.
Is it better to freeze or refrigerate seeds?
It is generally better to freeze or refrigerate seeds if you plan to store them for an extended period of time. For short-term storage, keeping seeds at room temperature in a dry, dark place is generally sufficient.
However, long-term storage, such as for multiple years, is best kept sealed in an airtight container in the freezer or refrigerator.
Cooling the seeds to below 40 degrees Fahrenheit will prevent the seeds from losing vital moisture, allowing them to remain viable for multiple years without losing valuable genetic material. Cool temperatures also slow down the activity of natural enzyme activity and delay oxidation in the seed, which can cause colors and pigments to fade.
Furthermore, cold storage in a sealed container prevents the seeds from being exposed to damaging temperature fluctuations, as well as pest infestations.
When freezing or refrigerating seeds, it is important to ensure that the container is airtight, as moisture and air can cause the seeds to become damaged and even rot. When ready to use, take out the amount needed, and then return the container with the remaining seeds to the freezer or refrigerator.
Do seeds germinate in freezer?
No, seeds do not germinate in the freezer. When seeds are kept at temperatures close to 0°F (-18°C), it is referred to as freezing. This type of environment is not suitable for germination as the cold temperature prevents germination from taking place.
In fact, lower temperatures will actually slow the germination process and cause the seed to eventually die. Some seeds, such as spinach or lettuce, may be able to germinate while in a frozen state, but this is not recommended as the seedlings that emerge may not be as healthy or as strong as they would be if they had been grown in more optimum conditions.
To ensure the best possible germination rate and seedling quality, it is best to keep seeds at a temperature of around 60-70°F (16-21°C).
Can I stratify seeds in the freezer?
Yes, you can stratify seeds in the freezer prior to planting. Stratification is a process used to break down the hard coating of some seeds and help them to germinate. Freezing the seeds can help to imitate a cold winter season and allow them to germinate more easily.
The best way to do this is to put the seeds in a sealed bag and place them in the freezer for three to four weeks. Make sure to leave the seeds in the bag during this time so that they do not freeze to the shelves or other items in the freezer.
After, remove the bag and place the seeds in water for about 24 hours. Then, strain out the seeds, spread the seeds over a damp paper towel, and place them back in the freezer for another three to four weeks.
Finally, remove the seeds and plant them in their desired location.
Will seeds still germinate after being frozen?
Yes, seeds will still germinate after being frozen. They must, however, experience the correct cold temperatures and length of time for the process to occur. Generally, seeds need to be exposed to temperatures slightly below 0 °C for a period of several weeks for them to successfully germinate.
The time frame can vary depending on the type of seed, but it is generally accepted that it can take up to 16 weeks for certain species. During the process of freezing, the cells and tissues in the seed will be damaged, but if done correctly, the cells within the seeds will remain intact, making it possible for them to germinate by utilizing their stored energy reserves.
Other factors, such as adequate oxygen and moisture, also play a role in the success of frozen seed germination.
Do seeds germinate just as well at a cold temperature?
No, seeds will generally not germinate as well at colder temperatures. Most seeds require a warm temperature, between 65 to 85 degrees Fahrenheit (18 to 29 degrees Celsius), in order to have a successful germination rate.
In cold weather, the soil temperatures are often too low for the metabolic processes of plants to occur, which can prevent and inhibit the germination process. Furthermore, at lower temperatures, a lower number of species will germinate, and the rate of germination for those species that do germinate will be slower.
Depending on the plant species, some seeds may be able to germinate at cooler temperatures; however, this is generally not recommended, especially for the average gardener.
What temperature is too cold for seeds to germinate?
The answer to this question is dependent on the type of seed you are attempting to germinate; different types of seeds have different optimal temperatures for successful germination. In general, the ideal temperature for seed germination is typically between 65-75 degrees Fahrenheit.
However, some seeds, such as lettuce and spinach, germinate at temperatures as low as 40 degrees Fahrenheit. On the other hand, some seed, such as tomato and pepper, require higher temperatures of at least 70 degrees Fahrenheit or higher in order to germinate.
In general, if the temperature is below 40 degrees Fahrenheit generally it is too cold for most types of seeds to germinate.
Is 40 degrees too cold for seeds?
It depends. Different seeds have different optimal temperatures for germination. Generally, if the temperature is too cold, the seeds will not germinate at all or the germination rate could be significantly reduced.
Some cool-season vegetable seeds including broccoli, spinach, collards, and cauliflower prefer temperatures between 40°F and 70°F and may have optimum germination temperatures between 50°F and 60°F. These seeds usually grow well in 40°F, but may take a bit longer to sprout.
Other crops such as tomatoes, peppers and zucchini should be started indoors, year-round and kept at a minimum temperature of 60°F, so a temperature of 40°F is too cold for germination. In temperate climates, summer vegetables should be planted when the soil temperature is at least 55°F, and some may require higher temperatures to germinate quickly.
The temperature should not exceed 90°F as this will stunt the seedling growth and increase the risk of fungal diseases. Therefore, it ultimately depends on the seed, as some may be able to germinate in 40°F, while others may not.
What seeds need freezing to germinate?
Freezing some seeds can actually be beneficial for germination and is deliberately done in some cases. The general idea is that freezing forces dormancy of the seeds and shocks them into pushing through the dormancy phase, allowing them to begin germination.
Freezing also assists in thinning out any extra dormancy barriers. Examples of seeds that require freezing or stratification in order to begin germination include Trientalis borealis (starflower), Rhododendron, shrub dogwoods, Amelanchier, and Prunus species like cherries.
Other types of seeds that may benefit from the cooling effect of freezing, but may not need it, include those from angelica, carrot, lily, and milkweed.
Is 70 degrees warm enough to germinate seeds?
Yes, 70 degrees is generally warm enough to germinate seeds. Ideal temperatures for germination range from 60 to 75 degrees Fahrenheit. Warmer temperatures may speed up the process, and most seeds will germinate at 70 degrees.
Cooler temperatures might delay germination or prevent it altogether. Make sure to keep a close eye on the progress of your seeds and adjust the temperature of your environment if necessary.