Seed Bombs

Via. Cool Hunting:

Seed bombs—a simple mixture of clay, fertilizer and plant seeds—are a favored form of DIY "drop-and-go" weaponry among gardeners taking the greening of public spaces into their own hands. To aid the expansion of the guerrilla gardening movement in its persistent goal of transforming forgotten or abandoned urban landscapes into greener spaces, L.A.-based design firm Common Studio came up with pre-made seed bombs.