Winter sowing is sowing seeds outside in winter in mini-green houses. The reason?
many seeds need a cold period (30-60+ days), called cold stratification, to germinate.
protects the seeds from birds and rodents
seeds germinate earlier
plants harden off naturally, and sooner
greenhouse effect creates larger seedlings
Most seeds can be started this way, depending on the seed and the temperature. IE, cold hardy or cold climate evolved plant seeds can be started in January, warm weather vegetables/plants early spring (April)
Materials: milk jug, scissors, drill, moist soil, garden marker, seeds, tags, duct tape, water can.
How its done:
Clean milk jug. (Other plastic containers can be used as well). No need to keep lid.
Poke drainage holes in lower sides with drill or scissors.
3. Cut hinge in milk jug, just below handle and from handle side to handle side.
4. Fill w/soil 1/2" below hinge edge.
5. Plant, including plant tag.
6. Tape hinge closed.
7. Label container w/garden marker.
8. Place outside out of direct sun. Don’t worry about cold/snow.
9. Keep soil moist.
10. When temps rise consistently above freezing at night, open hinge. Temps above 65 during day, open lid (lids can be re-taped closed).
11. When 2-3 sets of true leaves appear, separate seedlings in larger pots or plant in garden, if temps are ideal.
For more info, check out sowing seeds in winter online.