An artificial seed has a powder structure or powder padded layer as a sealing material for anti-contamination purpose. This powder layer, 2-30 mm preferably 5-20 mm in thickness, consists of numerous fine sandy hydrophobic particles. The openings among the particles are small and winding enough to block micro-organisms from penetrating this dry and nutrientless layer into the seed, but not enough to block the needed oxygen. The hydrophobic nature of the particles is also effective to block water permeation and microbes therein, but not effective to block the tissue to grow out of the seed. The powder layer can cover any exposed part of the artificial seed. For the artificial seeds with a water-proof tough shell, the powder layer covers only the mouth or mouths of the shell. But for those with a water-soluble capsule, or water-soluble film, it covers all over the contents of the seeds. In both cases, the powder layer is again covered with the water-soluble film to kept the powder particles in position. After sowing and watering the artificial seed in non-sterile soil, the water-soluble film is dissolved but the powder layer is still kept in position by the surrounding soil. The germination process is very much like that of a real botanical seed.

The present invention is characterized by coating a seed with from 0.1 to 25% by weight of a powder (A) composed of one or both of montmorillonite and bentonite and having an average particle diameter of 30 .mu.m or less and from 99.9 to 75% by weight of a powder (B) composed of a material other than montmorillonite and bentonite and having an average particle diameter of at least 10 .mu.m and at most 30 .mu.m using a polyvinyl alcohol aqueous solution having an aqueous solution viscosity at 25.degree. C. of 50 mPa.multidot.s or less as a binder. Consequently, a coated seed obtained by coating a seed, especially a light-favoured seed, easily absorbs water in sowing and is easily cracked in absorbing water. Further, the easy cracking thereof remains unchanged with the course of time. In the coating, formation of by-product seedless spherical pellets is little observed.

A method of preventing defective germination or growth of a plant is provided, by which even plant seeds having small size can be sown easily and securely. The method of preventing defective germination or growth of a plant includes the steps of: encapsulating plant seeds in an aqueous gel capsule; refrigerating the plant seeds under the condition that the plant seeds do not germinate; and sowing the plant seeds.

The present invention relates to the use of an agglomerated/granulated mulch product as a seed carrier that is produced by an agglomeration technology. The mulch agglomerates used as a carrier for the seeds reduces segregation (unmixing) tendencies of seeds from the carrier product.

This invention pertains to combination seed capsules wherein each seed capsule includes both moieties of at least one soil conditioner and at least one seed, and optionally, one or more inorganic chemical fertilizer, growth enhancer, binder, and/or anti-fungal agent. The combination seed capsules are made by physically combining the respective soil conditioner and seed with one other, in the absence of any requirement for chemical reactions in the process of so combining the respective materials. The combination seed capsules provide cooperative and beneficial effects of the soil conditioner and the optional inorganic fertilizer, working together in controlled intimate relation with the seed, to enhance the germination and growth processes of the seed, and the plant emergent therefrom, greater than when the soil conditioner and seed, and optionally inorganic chemical fertilizer, are applied to the soil separately; the improvement being a result of the intimate relationship of the respective materials in the combination seed capsule, whereby the respective materials cooperate with each other in support of germination and plant growth.