Convert spring fever into spring seedlings with Winter Sowing!
For “winter sowing”, we plant seeds in milk jugs or other semi-transparent plastic containers. Placed outside in January or February, these mini-greenhouses expose seeds to the cold temperatures that some wildflowers and other perennials need to experience before germinating.
How about broccoli, kale, or dill? The seeds of cool-season vegetables, leafy greens, and some herbs can also get an early jumpstart within these protected pots. In addition, it’s a low-cost way to raise hard-to-find plant varieties that are most available from seed.
In our February classes, students are planting many of the 32 donated jugs slated for winter sowing for HOPE Gardens. We bring the cut and labeled jugs ready for class, inviting each student to plant a seed and some to tape up the jugs before we place them outside. In many schools, students can glimpse these winter mini-greenhouses, nestled in their garden, from inside the school or parking lot.
For winter sowing, we prioritized flowers such as echinacea that attract pollinators but need cold exposure. We also selected annual flowers like bachelor buttons often requested by students but for which we lack room in the big greenhouse. We are also trying some challenging herbs like parsley that don’t sprout readily under indoor lights.
How to Winter Sow? Cut a washed-out milk or water jug almost in half just below the handle, leaving a hinge of plastic intact. Leave off the original cap. Poke several drainage holes in the bottom and add some holes on top as air vents. With the lid open, fill the bottom with four inches of potting soil and then moisten it.
Plant your seeds and label the jug with a permanent marker, even writing the plant’s name inside or under the jug as well. Tape the top lid securely onto the bottom half with duct tape. Place your mini-greenhouse in a sunny spot protected from strong winds and dream of spring seedlings sprouting within!