I am thinking of doing winter sowing for the first time, and have some coneflower, black-eyed susan, and marigold seeds I collected last summer. I also have some empty OJ/milk cartons that I was going to put inside plastic bags with slits.
However, I also have a long railing box and a couple small containers that still have some soil in them. The weather is a little warmer in Chicago and they might unfreeze a bit. I was wondering - can I just plant some seeds into there, or is it critical to have the containers be covered with plastic? I also sowed some seeds directly into our garden, and hope at least a few will come up there anyway. Thanks!