Encouraging the return of the worms in winter
I have a greenhouse structure--a 20' x 24' hoophouse in its third year of operation. It has decent loamy clay soil--compacts when wet, and is compacted at the deeper levels but otherwise is fairly ok.
I've been limiting water to kill off the weeds there, wild onions, creeping charlie and perennial grasses, but that has made all the worms and much of the soil life leave, too. The good news though is that I haven't had any aphids either, which were a bane on my kale last winter.
There are some areas that are badly compacted now from walking, and some area between bareroot tree starts that I won't be able to use for any plants for months. It's too early in zone 5 to seed cover crops, even with a hoophouse.
What can I do in the meantime to encourage the return of the soil life?
Put down a layer of dried leaves, rotted hay, compostable materials and water it down?
At some point, can I introduce some of the "red wriggler" worms from my colony in the basement? The purpose here would be to help compost the matter that I put down--I know they aren't soil dwellers.
The air temperatures in the hoophouse at 4 feet high range from 12 degrees Fahrenheit on really cold nights to high 80s on sunny, warm winter days.
Or should I do something totally different?