PURPOSE: To obtain the subject soil, used for germinating, rooting, acclimatizing and raising seedlings of a seed or a redifferentiated tissue under a sterile environment and capable of preventing the root from being deficient in oxygen and nutriments and water from outflowing without damaging the root by aggregating the soil into a granular or a stringy form with a gelatinous supporting material.

CONSTITUTION: This artificial soil is obtained by dissolving powder of sodium alginate in water so as to provide 3% concentration, then dropping the resultant solution into a CaCl2 solution prepared at 0.1 M concentration with a syringe, allowing the prepared mixture to stand for 30min, gelatinizing the mixture, forming a granular molded body composed of a gelatinous support having 20-50% voids, subsequently introducing the resultant molded body into a liquid culture medium without containing a phytohormone, permeating the liquid culture medium thereinto, then placing the granular molded body in a culture device and sterilizing the molded body in an autoclave. The artificial soil is used for germinating, rooting, acclimatizing or raising seedlings of a plant seed or a redifferentiated tissue under a sterile environment and capable of preventing the root from being deficient in oxygen and nutriments and water from outflowing to the outside and taking out the plant without damaging the root at all.