Do you know what kind of climate she was sowing in?

Open containers with grit works well for me in my mild wet winter coastal climate. Nothing ever needs watering or attention. I can't imagine how that would work in freezing drying winds.

I think one of the reasons wintersowing works so well for so many people is that the plastic coverings help to maintain a consistently moist environment. In nature I have observed the wonderful carpet of green seedlings that occurs following a rain. Unfortunately, if the rain stops and hot dry weather follows, many of those sprouts don't survive to grow bigger. But, inside the greenhouses, the moisture doesn't evaporate away as easily, so the fragile sprouts have a little more time to develop the deeper roots they need to survive future droughts.

Martha