Waste coffee husks and spent coffee grounds (SCGs) are produced in large qualities worldwide. Characterisation of these waste streams from Australian commercial outlets in terms of lipid, caffeine, and polyphenol content was undertaken giving values up to 10 % lipids and 23 mg g−1 phenols from SCGs, consistent with reports from other parts of the world. Husks generally gave lower values. Caffeine residues of 5 and 10 mg g−1 (dry weight basis) were found in husks and SCGs respectively. Comparing air-dried and water-extracted solid SCGs and the resulting water extract in plant phytotoxicity studies indicated that pretreatment of the SCGs and plants exposed to the SCGs, are important factors when considering their use as a soil amendment.