27 Plants That Need Cold Stratification

 

What is cold stratification?

Simply put, it’s the process that seeds go through naturally during the winter in colder areas of the world. Numerous plants’ seeds rely on an extended period of cold as a natural timer.

Many of these plants won’t germinate until they have experienced the cold temperatures of winter. Seeds, such as Milkweed, may also undergo hormone changes during this cold period that allow the plant to produce flowers (vernalization) the following year.

It makes sense that plants that grow in the parts of the world with harsh winters would need some sort of built-in timer to tell them when not to grow and when it’s okay to get growing. Otherwise, the seeds would hit the ground in the fall and sprout up, only to be decimated by the first frost.  

The cold temps of winter push the pause button on these seeds. Bingo! Cold stratification.

If you want to grow something from seed that you would normally find as a seedling, check the seed packet to see if it would benefit from cold stratification. Nearly all seed packets will note if stratification is necessary for germination.

Anise Hyssop (Agastache)

Artichoke (Cynara cardunculus)

Asparagus (Asparagus officinalis)

Beebalm & Bergamot (Monarda)

Black-eyed Susan (Rudbeckia)

Catnip/Catmint (Nepeta)

Chamomile (Matricaria chamomilla & Chamaemelum nobile)

Columbine (Aquilegia)

Comfrey (Symphytum)

Coreopsis (Coreopsis lanceolata)

Delphinium (Delphinium)

Dill (Anethum graveolens)

Echinacea (Echinacea purpurea and Echinacea pallida)

Larkspur (Consolida)

Lavender (Lavandula)

Lemon balm (Melissa officinalis)

Lupine (Lupinus perennis)

Milkweed (Asclepias syriaca)

Mints (Mentha)

Mullein (Verbascum thapsus)

Phlox (Phlox)

Poppy (Papaver)

Rosemary (Salvia rosmarinus)

Sage (Salvia officinalis)

Snapdragons (Antirrhinum)

Verbena (Verbena officinalis)

Yarrow (Achillea millefolium)

 

You will note there are only a couple of vegetable seeds on this list. That’s because most of the vegetables we grow in our gardens each year have been highly cultivated over the centuries to achieve the forms we’re so fond of today. Most are grown as annuals without the need for cold stratification.

The few vegetables that do need stratification are perennials, which you would plant once and tend the resulting plant thereafter, such as asparagus or artichokes. Annuals that require cold stratification, such as the allums – garlic, scallions, onions, etc. – are usually planted in the fall or very early spring so as to be cold stratified naturally.

How to Cold Stratify Seeds the Easy Way

While there are numerous methods for cold stratification, your fridge is generally the only tool you need. Well, your fridge and a quart mason jar with a lid.

Place your seed packets in a clean mason jar with a desiccant packet (these silly things come in handy more than you would think) and put the lid on. Pop it into the fridge for the recommended time for each seed. The desiccant packet will keep the seeds and paper packets from getting all damp and gross.

When it’s time to plant your seeds, take the packet out of the fridge and follow the directions for sowing. It really is that simple.

Now, some seeds do better with moist stratification – cold and wet – just like real winter! You can place them on damp paper towels and place them in a plastic bag in the fridge. But I’ve always had terrible luck with this method. I usually end up with rotted seeds.  

Instead, once they have spent their cold spell in the fridge, I soak my seeds in water in the fridge overnight the day before I plan on sowing them. This is much easier, and I’ve always had success with it.

Most seeds will usually germinate even if you only dry cold stratify them, although they may take longer to germinate. Too often, we get wrapped up in must-dos in gardening that are arbitrary and manmade when there are lots of ways to get the job done.

I don’t know if you have noticed, but Mother Nature never sticks to a strict schedule or precipitation amount when it comes to winter, yet her flowers are always beautiful.

If she can fudge cold stratifying a bit and still get good results, you can, too.

Source: ruralsprout.com©

Related:  Seeds to Start in the Winter and Early Spring – TUTORING YOU