Nine chemical products were tested for ripening activity in immature, glasshouse propagated sugar-cane under condition designed to bypass major field variables and to offer rapid information on their probable potential. Nitrogen and water supplies were held constant at levels assuring steady but not luxuriant growth. All leaf surfaces were thoroughly wetted with two concentrations of each chemical. In addition to growth and quality measurement, the activity trends for acid invertase, ?-amylase, acid phosphatase and ATPase were analysed for evidence of chemical penetration and activity. Of the nine materials tested, chlormequat chloride and 60-CS-16 gave evidence of ripening potential sufficient to justify testing in field plots. Marginal responses to Alar-85 and 2-chloroethylphosphonic acid warranted further glasshouse evaluation. Dicamba showed a leaf sheath loosening property having possible value in canopy penetration or defoliation studies. Seven compounds gave evidence of penetration and physiological activity of some kind, but none of the materials significantly repressed growth.