Time series of repeat-pass interferometric coherence measured from Sentinel-1 images (C-band) and TerraSAR-X/TanDEM-X and PAZ (X-band) have been evaluated for crop monitoring and crop classification. Temporal decorrelation at X-band has been studied in detail thanks to the availability of multiple temporal baselines (4 days, 7 days, 11 days, 15 days, etc.). Different responses are found for different crop classes and also depending on the growth condition of the plants. Based on such a sensitivity, crop classification using series of C- and X-band coherence as input features has been also evaluated, showing the contribution of interferometry in this domain.