This is a great science activity that can be used throughout the whole year, with minimal planning and maximum learning!
Just pick a tree by your school, and visit it throughout the seasons, first in the fall, then winter, then spring, and in the last week of school for "summer." Have the kids draw an accurate drawing (age-appropriate) of the tree in each season.
We use this in connection with our FOSS science kits in K.
If you're interested in more Kindergarten Foss Resources, check out this bundle! It includes 17 printable pages to supplement the K Foss Curriculum! Kindergarten Science Unit