 This paper examined the potential of Sentinel-1 synthetic aperture radar, SAR, to monitor crop conditions. It found that the cross-ratio, CR, which is calculated from the ratio of VH to VV backscatter, was the most effective indicator of vegetation dynamics. The CR was able to explain up to 87% of the variation in vegetation water content, VWC, for corn and 63% for winter cereals. Additionally, it was shown that the CR could be used to predict VWC with an accuracy of 0.34 for oilseed rape. Furthermore, random forests were used to analyze the relationship between CR and other variables such as soil moisture and microwave indices. These results suggest that the CR is a reliable indicator of VWC and can be used to accurately predict crop growth. This article was authored by Mariette Rugdenhill, Wolfgang Wagner, Bernhard Bauer-Marschlinger, and others.