Water in plants is one of the most important factors for life. Water availability, water distribution and water flow also regulate various plant physiological phenomena. However, non-destructive methods for the in-situ study of water transport are quite limited. Neutron Radiography (NR) seem to be appropriate methods to study water distribution in intact plants. Also the combination of NR with the low-contrast tracer D2O allows the direct visualization of water flow and the calculation of water flow rates in plants with a high resolution at the tissue level. This article gives general introduction into those two methods and report about most recent results of our experiments in this field.