Did you hear the birdies start chirping last week? Here at Deep Harvest, the robins are back to singing sweet songs of cereal (their AM chirps sounds like “cherrio, cherrio”) and the sun is showing its face. We know this means that you likely want to get your hands popping seeds into that cold muckiness. Ok, ok- at this point, we’ll allow it.
Lucky for you eager growers, some flowers actually like the cold soil. Who are these brave blooms? They go by the names Poppy, Larkspur, Rudbeckia, Catmint, Chamomile, Eryngium, Sweet Pea and Nasturtium. They’re the open-ocean swimmers of the flower world, not only tolerating frigidness, but even basking in it. (I’m an open water swimmer of the human world, so I understand!). We direct sow all these seeds in early to mid-March. However, if you’ve had trouble getting any of the aforementioned flowers to germinate, you might want to take tending to them to the next level. This crew appreciates being stratified or scarified! Eeee. Sounds scary, but it’s merely scar-y. Here’s the skinny on how to grow the frigid-est of flowers.
Stratification is a process of seed stimulation to promote germination. Most seeds experience dormancy as embryos, which must be broken somehow. In nature, seeds spend significant time in the ground during winter rains and frost which softens their seed coats. In your home, you can mimic this process by dampening a paper towel, sprinkling the seeds on it and folding the towel around the seeds. Place this bundle in a labeled plastic bag, seal it, then mark your calendar so you remember to take them out of the fridge after a month! At that point, you can start your flowers as you normally would. Larkspur, Rudbeckia, Catmint, Chamomile, Eryngium all may benefit from this process.
Scarification: Some seeds have extremely hard, protective coats, which can make it difficult for them to germinate. The whole point of a seed having a tough coat is to prevent it from germinating at the wrong time. To overcome this protective mechanism, you can nick the seed with sandpaper or an emery board. You can also just soak them in water overnight before planting. That causes seeds to swell, which in turn breaks the outer seed coat. Sweet Peas and nasturtium may benefit from this process. At Deep Harvest, we always pre-soak our sweet peas, whose coats are particularly hardcore.
You may also have heard of Vernalization which is process that initiates flowering in plants (rather than germination of seeds) by exposing them to prolonged cold temps. Vernalization doesn’t apply to seed starting, but if you’re interested in growing root crops for seed, explore this concept further here: https://www.growveg.com/guides/vernalization-of-winter-vegetables-for-seed-saving/