Welcome, newcomer. Traditionally, winter sowing commences on the Winter Solstice, December 21. Sowing seeds on that date honors tradition but it also makes practical sense. Many (not all) seeds need a period of cold stratification (read: freezing cold) in order to sprout. Seeds that fall into this category generally include certain perennials, shrubs, trees, etc.

I'm guessing your USDA climate zone where you are is Z5 or Z6. You can Google your ZIP Code to get your zone. I'm in southern New England in Z6a.

Winter sowing (at least for me) was a way to grow LOTS of perennials to fill my garden beds for a tiny fraction of what they'd cost if I bought them from a nursery. I won't bore you with the details but I wanted perennials to sustain bees, butterflies and hummingbirds. So far this season I've seen a hummingbird twice so I'm guessing I grew the right plants.

I garden organically and use NO chemicals to control weeds.

Growing in recycled containers accomplishes several goals: 1) Perennial seeds know when to sprout based on the moisture of the soil in which they're sowed + hours of daylight + temperature. Seeds grown via winter sowing sprout when their genetic code tells them the time is right. 2) Winter sown sprouts are already acclimated to the fluctuating outdoor temperatures when they sprout and are less likely to be bitten by frost. 3) The moistened growing medium (i.e., potting mix) in which the seeds are sown provides the water plants need to develop healthy root systems. Wintersown plants develop the most AMAZING roots!!

I hope I've answered your questions but feel free to ask more as they occur to you. I have an elegant garden on my little green acre that's filled with hundreds of winter sown perennials. Sorry--haven't figured out how to post photos since Houzz took over the forums.