Some seeds, like perennial Sweet Peas or Pansies, require special care in order to break dormancy and germinate. If you’ve ever questioned why certain seeds from brand-new plants never seem to germinate, cold stratification might be the answer.
Stratification sequences may differ, according to Master Gardener Susan Patterson: “Some seeds demand a warm and moist treatment, while others require a cool and wet treatment.” Other seeds, however, need a mix of warm and cool treatments, followed by a warm treatment, or a warm and cool moist combination, followed by a dry cycle and a warm phase. Before starting any seed stratification endeavor, it is essential to understand what seeds need to emerge from dormancy. In order to expose the seed to air and moisture, certain plants also require stratification from heat, such as from fires.
Cold and moisture are the two main conditions for cold stratification. It is better to plant when winter is expected to last, depending on where you reside. The seed coat can break down and there may not be much germination if you sow when it’s too warm.
However, if you are starting in the early season, soak your seeds for 12 to 24 hours before placing them in a plastic bag or other airtight container with sand, peat, or an equal mixture of the two. Label and date. See if they are sprouting frequently. Some seeds must be stored in the freezer for a longer time than others.
According to Pinetree Garden Seeds, “soaking them in cold water for 6 to 12 hours prior to beginning the process can help reduce the overall stratification time needed. Additionally, this aids the seed in absorbing some of the moisture it needs for the upcoming chemical processes.
1) If your plant reseeds, you can simply disperse your seed as soon as it seeds if it doesn’t matter where the new growth appears. Any unruly plants that sprout up against your garden plan can be moved to where you might decide you want them, given away as a last resort, or eaten if it is acceptable, or composted. For breadseed poppies, I employ the broadcast technique. However, occasionally you might change your garden layout to make room for what you hope will turn out to be a magnificent display of beauty!
If you have a seed packet, a more formal approach would be to choose the location, prepare the soil, and scatter your seeds there in the fall. Put a tag on the location, date, and information. Keep them moist; when they are ready, they will sprout.
Floods or drastically changing weather, such as cold, hot, and cold, could be risks of these two strategies. Just in case, keep some extra seeds on hand. Then you move on to way #2, or you can practice both method 1 and method 2 just in case.
2) You might apply the paper towel technique. Put the seeds on one side of the towel, moisten it, then fold it over to cover them. Place the towel inside a plastic bag and zip it up. Place it in the refrigerator and wait. Some advise checking every two to three days and getting rid of any mold. Others advise waiting 10 days. Some estimate that it could take a month or two. They should be thrown away if they develop brown spots around them or begin to smell musty. However, the key goal is to keep that towel damp!
If you already have a seed package, here is myseedneeds’ recommendation for poppies for the lazy gardener! We advise a brief cold stratification period of 6 to 12 weeks, but gardeners who don’t want to deal with damp paper towels and plastic baggies can just store their seed packets in their crisper drawer for a few months.
You could also soak your seeds first. Put equal amounts of sand and peat in a pot and add worm castings to aid with germination. Place your seeds in. Put the pot or container inside the refrigerator, on the ground in a protected area, or buried up to the pot’s top on the north side of your building, which is more exposed to the elements. Keep those seeds moist at all times.
Restoration Seeds published this thorough guide to How to Germinate Your Seeds on Permaculture News. It gives more alternative Cold Stratification methods and incorporates them! starting at the Cold Stratification section. Great advice! Read this!
Harold and the Cats of Alchemy make a crucial point about sustainability: “Seeds…won’t come up all at once, way the seeds of most cultivated plants are bred to do.” Because they are more like to the wild and hence have a solid motive to stagger their germination, seeds that use cold to germinate are more likely to survive and produce more genetic variation. This implies that there will be a higher possibility of receiving plants that will thrive in your environment.
On a seed packet, terms like “self-sowing,” “perennial,” “cold hardy,” or “cold stratification” are signs that your seeds might benefit from cold treatment.
Numerous Common Domestic Flowers are significant companion plants, including Sweet Peas, Zinnia, Johnny Jump Ups, BreadSeed Poppy, Cosmos, and Pansies.
Wildflowers! Here is a great MAP to help you choose local wildflowers that need to be cold-stratified before being planted in the spring in your area. United States Meadows Native wildflowers make excellent companion plants because they draw local bees. Make sure to start early enough to allow for planting time because they need to stay in your fridge for 4 to 5 weeks. Your seeds will grow nicely and germinate more quickly. For monarchs, don’t forget to plant native milkweed!
Numerous perennial common herbs serve as significant veggie companion plants, food for pollinators, and companion plants: Sage, Rosemary, Lavender, and Calendula
Make careful to look up each plant separately to learn about its unique requirements, such as length of time and temperature. An illustration of the perennial Oriental poppy (Papaver orientale) can be seen at SFGate. Some poppy varieties are easy to plant, whereas Oriental poppy varieties require special care!
- In a plastic bag, put 2 tablespoons of perlite or sand. It should be mildly dampened with water, but not made soggy.
- Mix 1 tablespoon of poppy seeds with the perlite or sand before adding them to the bag.
- For two weeks, store the sealed bag in the fridge. Check on it every so often, and if additional water is required, give it some, to keep it moist. Keep it from drying out.
- Take the bag out of the fridge, and keep it somewhere cool and dry for a week. Put the bag back in the fridge for an additional two weeks.
- For six weeks to three months, repeat this cold-thaw cycle. In the early spring, scatter the layered poppy seeds over moist soil. When the soil temperature is between 55 and 60 degrees Fahrenheit, they will begin to sprout in about two weeks. [Therefore, begin your procedure well in advance!]
Cold stratification is a straightforward method that, while it may need some commitment, definitely pays off!
Should sweet peas be scarified?
Sweet pea flowers may be delicate and aromatic, but their seeds are infamously tough on the outside. Myers advises properly scarifying each seed (which entails weakening the seed coat) before planting in order to hasten the germination process, which can take up to three weeks. She says you can accomplish this by lightly scratching the seed coat with a nail file or piece of sandpaper. To help soften their “shell,” sweet pea seeds can be be soaked in water for about eight hours. Godfrey advises soaking seeds in wet paper towels over night so they’ll be ready to sow the following day.
Do sweet pea seeds need to be soaked before planting?
To aid in seed germination, many individuals advise soaking seeds overnight before sowing. This is due to the hard outer shell of some types. Others, though, contend that soaking might make plants weaker.
However, you might try slightly shattering the seed’s outer shell right before sowing if you’ve previously had difficulties getting the seeds to germinate.
On the side opposite the seed’s black “eye” or scar, carefully nick the shell with a sharp knife or rub it with sandpaper.
Do pea seeds need to be scarified?
Summary A stiff seed coat on many older heritage types of peas can cause uneven or delayed germination. We wanted to find out if pre-germination procedures like soaking or scarification—which involves abrading the seed coat—would indeed promote germination.
Despite the fact that many of them (2633 percent) only reported a very minor improvement, just over half of participants (57 percent for soaking and 61 percent for scarifying) observed an improvement in germination. When these effects were measured, they were really fairly minor, with both soaking and scarification shortening the time it took to reach 80% germination by about 1 day.
Participants were asked if they would try soaking or scarifying pea seeds again in the future. Of those, 32% said they might, and 50% said they were extremely likely or very likely to. Scarifying was less well-liked, with 53% of participants declaring they would never attempt it again.
The meager benefits from soaking and scarifying would suggest that, in most circumstances, they are not worthwhile, and more focus should be placed on producing ideal conditions for germination, such as a firm, flat seed bed, the proper levels of moisture, and ideal temperatures (above 10oC for germination).
Background The thick seed coat of many older round pea types might cause uneven or delayed germination. A latent embryo and a starchy food source can be found in a pea seed. It can only germinate when the embryo and the starchy food source are rehydrated. This process can be significantly slowed down by a stiff seed coat, especially if the seed is in soil where moisture distribution may not be uniform. Before putting the seed outside, partially soaking it in water will weaken this coat and start the germination process, which considerably speeds up emergence. This procedure is often referred to as “priming.” The hard seed coat can also be damaged or chipped away at to remove germination inhibitors. This procedure is called “scarification.” In order to accomplish this, the seed coat can be mechanically abraded using sandpaper, or a small nick can be made with a knife or nail clippers. The latter is only workable for a limited number of expensive seeds. Scarification is frequently carried out to enhance the germination of legumes like sweet peas, albeit its effectiveness depends on the type of seed used. To prevent damaging the embryo, the seed must be carefully abraded.
Varieties Four heritage variants were examined:
- Espoir de Gembloux is a Belgian cultivar that yields a large quantity of “melt in the mouth” peas.
- Frueher Heinricha is a tall German cultivar that yields consistently good crops.
- Latviana robust, tall, and productive pea that is eatable raw