Michael Bernstein found old versions of Jim Bones's seedballs.com domain (now apparently defunct) in the Internet Archive's Wayback Machine: Seedballs.Com Wayback Archive
A MightyMur tweet alerted me to the following Kickstarter project, "GreenAid seedbomb vending machine for greener cities".
Seedballs: from Fukuoka to Green Guerillas by Kirsten at Planting Milkwood.
Red Terra Cotta Powder v. Wet Modeling Clay at my blog.
Google web search for "seed balls" (favored over "seedballs").
Thanks to Al Pasternak of the Vancouver, BC Guerrilla Gardening Group,
for the seedball "recipe" and links to different sources:
5 parts clay, 3 parts soil, 1 part seed, 1 - 2 parts water
A. Dry terracotta clay, finely ground and sifted through a strainer to remove large chunks of clay. Amount: 1 1/4 cup
B. Dry organic compost. Amount: 3/4 cup
C. 1/4 cup assorted seeds*. Various wildflower & vegetable seeds can be used.
STEP TWO: Mix B & C together. (Seed mixed with dry compost.)
STEP THREE: Add A to B & C mix. Blend everything together well. Next, mist water onto the mixture while stirring. Spray just enough water to allow the mixture to stick/bind together.
STEP FOUR: Take a pinch of the finished mixture and roll (in the palm of your hand) into penny-sized round balls.
STEP FIVE: Put seed balls in the sun to dry completely for a day or two.
STEP SIX: Broadcast seed balls onto dirt area. Water or wait for rain to allow seeds to germinate.
Makes approximately 30-40 balls Hosted on PermaKent's domain served by an account on PermaHost, which is a project of PermaWorld.