Seed balls, also known as "earth balls", nendo dango (Japanese: 粘土 団子?), boule de graines in French, consist of a variety of different seeds rolled within a ball of clay, preferably volcanic plastic red clay. Into this medium various additives may be included, such as humus or compost. These are placed around the seeds, at the center of the ball, to provide microbial inoculants. Cotton-fibres or liquified paper are sometimes mixed into the clay in order to strengthen it, or liquified paper mash coated on the outside to further protect the clay ball during sowing by throwing, or in particularly harsh habitats.
The technique for creating seed balls was rediscovered by Japanese natural farming pioneer Masanobu Fukuoka.  In modern times, during the period of the Second World War, this Japanese government plant scientist working in a government lab, Fukuoka, who lived on the mountainous island of Shikoku, wanted to find a technique that would increase food production without taking away from the land already allocated for traditional rice production.  which thrived in the volcanic rich soils of Japan.
To make a seed ball, generally about 5 measures of red clay by volume are combined with one measure of seeds. The balls are formed between 10mm and 80mm (about 0.4 to 3.15 inches) in diameter. The patent has been deemed unenforceable throughout the world because of the ancient practice.
Seed balls have use in nearly any region where plants can grow: for reseeding ecosystems into areas of man-made deserts, avoiding seed eating insects and animals and protecting seeds until rains fall to soak the clay ball and stimulate the seeds. Seeds contained in such balls then germinate in ideal conditions for each climate/region.
- Adler, Margot (April 15, 2009). "Environmentalists Adopt New Weapon: Seed Balls". NPR. Retrieved November 9, 2011.
- Fukuoka (福岡?), Masanobu (正信?) (1978 May) [1st publ. in Japanese 1975 Sept. 『自然農法・わら一本の革命』 (shizen nōhō・wara ippon no kakumei)], The One-Straw Revolution An Introduction to Natural Farming, translation: Chris Pearce, Tsune Kurosawa, and Larry Korn (ed.), Emmaus, Pennsylvania: Rodale Press, ISBN 0878572201
- Fukuoka (福岡?), Masanobu (正信?) (1987 Dec.) [1st publ. in Japanese 1975 Dec. 『自然農法 緑の哲学の理論と実践』 (shizen nōhō midori no tetsugaku no riron to jissen); 1st Eng. tr. ed. 1985], The Natural Way of Farming The Theory and Practice of Green Philosophy, translation: Frederic P Metreaud (rev. ed.), Tokyo: Japan Publications, ISBN 978-0-87040-613-3
- Mixtures by Fukuoka Masanobu in his patent for advanced seedballs, titled "Paper/seed-unified planting seed unit and preparation process thereof"
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- "What's a clay ball?" and "Clay Ball Method" advice derived directly from Fukuoka Masanobu by The RainMaker Project, a major project in Africa by Yokohama Art Project, Japanese NGO.
- Masanobu Fukuoka re-invented seedballs (in this era), this is his patent for advanced seedballs, titled "Paper/seed-unified planting seed unit and preparation process thereof"; There's his previous earlier Japanese patent for less advanced seedballs - where's that?
- Making Seed Balls, by Jim Bones, he learned personally from Fukuoka Masanobu and from his books.
- "Seed Balls by Masanobu Fukuoka 1997" YouTube 18:43 long video, caption: "Natural Farmer Masanobu Fukuoka conducts a workshop for making seed balls at his natural farm and forest in Japan."
- Making Hay with Clay - Greece
- How to make seedballs
- A discussion of the pros and cons of different seed ball recipes
- 'On Seedballs', a website dedicated to seedballs
- Seed Bomb R&D forum come read and discuss about seed balls.