Abstract: A sheet material (4) for use in cultivating plants comprising a body having a coilable flexible, fluid-permeable structure and a plurality of passages (7,9) formed in and extending from one surface (3) to the another (5) of said body. The passages serve to induce root tips to grow and contain fertilizers. The body has at least one surface formed with projections and/or recesses. Preferably, the surface having projections and/or is provided with a ceramic powder discharging infrared rays of wavelength in the range of about 5 to 15 micrometers, a elution-rate controlling growth regulation fertilizer and a small amount of a chosen element. In use, a given length of the sheet material is wrapped around the plant.