Seed bomb

A seed sprouting from a seed bomb.

A seed bomb (also called a seed ball) is a ball made from a clay and compost mixture with a seed placed in the middle that was invented by Masanobu Fukuoka. They recreate idealistic germinating conditions found in the topsoil and used by throwing them upon to the ground to plant in inaccessible locations due to terrain or other barriers. Seed bombs are a popular tactic used by guerrilla gardeners who tend abandoned or neglected land that they do not own, such as abandoned city lots or road medians.

Making seed bombs

Make a seed matrix:

1. Mix 1 part compost to 5 parts powdered clay to form a basic seed matrix.
   • Sifted compost works best.
   • Additional ingredients can be included, such as:
     • Rock dust
     • Activated biochar
     • Mycorrhizal fungi spores
     • Cayenne pepper to deter some insects or animals from eating the seed
2. Store the prepared seed matrix in a dry environment until needed.

Forming seed bombs:

1. Add the desired amount of the seed matrix into a mixing bowl. One cup makes approximately 100 seed bombs.
2. In small increments, add water to create a pliable dough-like consistency. Add more water if crumbly or more matrix if soupy.
3. Form dough around each seed into miniature marshmallow-sized balls. Use two or more seeds per ball if the seed germination rate is below 90%. Slightly flatten the balls to sow on sloped terrains or use novelty ice-cube trays for fun shapes.
   • Consider using different molds for different seeds.
4. Let seed bombs completely dry in a warm or sunny room, typically one day.
5. Sow or store your seed bombs in a breathable container. Use within the year or the "best before date" on any seed packaging.

Seed coating might be a method to make a large number of seed bombs.