Seed balls are small bundles of seeds, clay, and soil or compost. Although seed balls have been around since ancient times, they were rediscovered in the 1930s by the Guerilla Gardening movement as a way to covertly introduce vegetation by simply tossing the seed balls (or, on a large scale, dropping them from an airplane). This activity is great for all learners and fun and inexpensive way to learn about native plants. View Resource »