For an avid gardener, January can be a difficult time of year. Sure, we can dream. The seed catalogs that have been arriving for a month now are filled with post-it notes, dog-eared corners, and bright yellow highlights. At the same time, I’ve decided and re-decided (at least a dozen times) where I’m going to plant each seedling once the weather warms. I love the optimism of dreaming, but sometimes I just want to get my fingers into some soil—even if the “soil” came out of a bag of potting mix.
At this time of year, gardening outside is pretty much impossible. The ground is frozen, and there’s still a layer of snow in the shadows on the north side of the house. Besides, it’s cold out there!
Happily, there are some seeds we can—must—start now, in January. These seeds fall into two groups—those needing a winter chill (stratification) in order to germinate, and those that simply take a long time to reach transplant size. Both are started the same way—you sow them in fine, dampened potting mix. (See detailed steps in my series on starting seeds; choose “seed starting” from the list of categories at left).
The only difference is that normally we immediately place the sown seeds in a warm place to germinate, but those needing a cold treatment are first wrapped in plastic (to retain moisture) and then placed somewhere cold—the refrigerator, freezer, or outside (depending on where you live)—for two to three months.
Alternately, you can sow these seeds on damp paper towels, then roll them up and stick them in a sealable plastic bag. That way, you can see whether they’re rotting or germinating. If they start to grow, plant them at once. Otherwise, once the cold period is over, go ahead and plant them anyway, according to their needs.
Seeds needing stratification can be planted any time during the fall, but January is your last chance to sow them and still get in the required chilling period.
Many perennials require this cold treatment. Some examples include lady’s mantle (above left), milkweed, false indigo, butterfly bush, bluebeard (false spiraea), German statice, perennial sunflower (Helianthus), false sunflower (Heliopsis, above right), coral bells, perennial candytuft, Knautia, perennial sweet pea, lavender, catmint, evening primrose, Penstemon, fleeceflower, Phlox, balloonflower, pasqueflower, prairie coneflower (Ratibida), Rudbeckia, soapwort, pincushion flower, Sedum, Stokes’ aster, and speedwell (Veronica).
Often, shrubs and trees also need stratification, especially Colorado natives. In fact, when it comes to our local native plants, it’s safe to assume that they all need a cold treatment. At the very least, it won’t hurt.
Seeds that take a long time to germinate and/or grow include candytuft, delphinium, geraniums (Pelargoniums, top), heliotrope, impatiens, matricaria, pansies, primula, rudbeckia, snapdragons, violas, wax begonias, oregano, parsley, leeks and onions. They should all be started by the end of February, at the latest.
Some seeds benefit from both a cold treatment and an early start. Violas (right) and delphiniums, for example, germinate better when first subjected to cold temperatures. But even once they start to grow, they take many months to become good-sized seedlings.
Winter is a time when most gardeners take a well-deserved rest. However, I’m glad there’s something we can do now. It may be freezing outside, but under my plant lights, it’s already spring.