Hi Meg,
I run after school garden clubs that run the whole school year and on the secondary level have a rotating crew of students who show up.
The following stand-alone activities I find work well for winter:
1) Winter Sowing (in milk cartons)
2) cold frame construction
3) Winter greens exploration (tasting/making a quick salad)
4) Know Before You Grow - how to read a seed packet
5) Seed transport
6) bulbs
7) root crop exploration (tasting, making a slaw or mashed potatoes etc)
8) Seed dissection
9) Composting (from vermicomposting to building a composter to soil web of life to decomposition activities etc etc)
10) testing seed viability
11) Making assemblages/mandalas out of what is in the winter garden
12) Bird activities (making seed balls, bird houses etc)
Hope this helps!
Rebekka Henriksen (she/her)
Farm to School Project Manager