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UC Master Gardeners of San Luis Obispo County

Planting Seed Balls

Seed Balls: A Simple Way to Sow

By Priscilla McGee, UC Master Gardener

What Is a Seed Ball?

Seed balls are seeds wrapped in a mixture of clay and a nutrient source such as compost, manure, or potting soil. They function as complete planting packages. The clay protects seeds from harsh environmental conditions and allows for delayed germination.

Seed balls are useful in neglected, damaged, or remote areas, and in locations with low or inconsistent rainfall.

Seed ball example

Photo Credit: Extension Master Gardener Volunteers of Buncombe County

History

Seed balls were used in ancient times to preserve seeds for planting in semi-arid or flood-damaged lands. In the early 20th century, Japanese farmer Masanobu Fukuoka revived the technique, calling them “earth dumplings.” More recently, seed balls—often called seed bombs—have been used in guerrilla gardening to rehabilitate neglected urban areas and restore fire-damaged landscapes.

How It Works

The clay absorbs and retains moisture while compost supplies nutrients. The dry shell protects seeds from sun, wind, birds, and insects. When sufficient moisture is absorbed, seeds germinate inside the ball. Eventually, the clay dissolves, allowing seedlings to root.

Seed balls require no digging or soil cultivation. They can simply be placed or tossed onto the ground—even distributed across large or hard-to-access areas.

Advantages

  • Can be stored long-term; use glass, paper, or cardboard—not plastic.
  • No digging required; suitable for gardeners of all ages.
  • No precise timing with rainfall needed.
  • Effective for steep slopes, forests, rocky soils, and remote areas.
  • Reduces labor, cost, and soil disturbance.
  • Fun and easy project for children.
  • Works with wildflowers, edible crops, trees, or mixed seeds suited to the site.
Making seed balls

Photo Credit: https://art.ucsc.edu/sesnon/events/seed-ball

Seed Ball Recipe (Makes ~18)

  • 1/4 cup commercial clay powder
  • 1/4 cup coarse compost (or 1/2 cup fine compost)
  • 2 tablespoons water
  • 2–4 seeds per ball

Directions

  1. Mix clay, compost, and water to a putty consistency. Add water as needed.
  2. Take approximately 1/2 teaspoon of mixture, flatten in palm, insert 2–4 seeds, and roll into a ball.
  3. Allow to dry in shade for 2–3 days.
  4. Store in glass or cardboard (not plastic) until ready to use.
  5. Toss onto desired area.

Additional Tips

  • Clay powder is available at ceramic or art stores.
  • Basic ratio: 2:2:1 clay:compost:water.
  • Nutrient source may be compost, manure, or potting soil.
  • Add a small amount of local soil for beneficial mycorrhizae.
  • Include cayenne pepper if animals disturb seed balls.
Finished seed balls

Photo Credit: https://extension.psu.edu/programs/master-gardener/counties/franklin/news/2016/seed-balls-have-it-all

References