Now is the perfect time to plant your native seeds
Often we think of spring as the sowing season, but for native plants, sowing in winter is usually the ideal time, with some species like Stoneroot, Golden Alexander, Gray's Sedge, and Late Boneset potentially seeing better germination if planted outside in late fall. Some plants like Purple Coneflower and the milkweeds we offer don't necessarily need a cold period to germinate, but germination rates will likely be better if the seeds experience at least some cold.
The two main methods for exposing seeds to cold are outdoor planting (either broadcasting seed or sowing in pots) or placing seeds in containers of inert material like sand and using your refrigerator to simulate winter in a process called "cold stratification." We note the recommended number of days of cold stratification for those species that need it with "Cold(30)" or "Cold(60)" or "Cold(90)". We have used both methods, but find that planting outdoors is generally easier because once you’ve planted, there is no need to do any work for weeks or months for the germinating plants.
If you start plants indoors after cold stratification, it’s best to harden them off before putting them outside permanently (placing them outside for progressively longer periods over a series of days), whereas with outdoor-raised plants there is no need for work like that. But you can't overlook the major benefit of indoor sowing - your plants will be much further along in their development by the time spring rolls around and you can then transplant them into the garden much sooner. As a bonus, with native plants, which often bloom naturally in the second year if seeded outdoors, you can sometimes get blooms in the first year by sowing indoors in winter.
Indoor planting has some potential pitfalls though. If the potting mix is too damp for too long, your plants can succumb to damping off disease, with symptoms including narrowed stems at the soil line, growth that stops abruptly, after which seedlings look sickly and eventually die. To combat damping off, it can help to water the bottom of a tray and let water travel up the soil if using smaller pots or trays with cells rather than watering them from above. If you're not using grow lamps and heating mats and primarily relying on sunlight as your light source indoors, you should also avoid watering plants at night because doing so increases the chances that damping off will occur.
Regardless of whether you are planting pots indoors or outdoors, we recommend using a peat-free compost-based potting mix. Peatlands make up a low single digit percentage of the world's land surface, but are massive carbon sinks, help prevent flooding by absorbing water during rainstorms, and are important habitats for many species. They also form incredibly slowly over a period of hundreds or thousands of years - not exactly an easy-to-replace resource once removed.
We have tested compost-based mixes available from retailers that have worked well and created our own mixes using organic compost, coconut coir, and rice hulls. Other than potting mix and pots (if you are planting in pots and not broadcasting seed), you will need labels and pencil to write the name of each species on. For outdoor planting in open pots, we follow Wild Seed Project's advice in adding coarse-grained sand on top once you have seeded the pots. The sand helps shield the seeds from being knocked out of the pot during rain storms. A general rule of thumb for planting native seeds is to plant them no no deeper than the width of the seed you are planting. Often you can surface sow them, especially if applying a top layer of sand. The last step is to place the pots in a shaded place outdoors, lay a rodent screen with a 1/4 inch mesh on top to prevent squirrels from digging in your pots and then let winter work its magic. Usually you will see germination in outdoor sown pots starting in late March or early April, depending of course on how cold the winter was!
We love winter, all of the planning, planting, and imagining and hope for the new growing season, the possibilities inherent in new experiments and new native species to grow. And if we're lucky, those planting experiments will lead to a greater diversity of insects and birds in the garden, making our world a richer place for all.
On to new growth - and happy planting!
-Andrew