Microwave near field microscopy and spectroscopy are currently studied for imaging and local characterization in material science, as a non-invasive diagnostic technique in many fields of interest, encompassing dielectric, magnetic and biological samples. Monitoring cultural heritage artefacts is also possible measuring biodeterioration by near field microwave microscopy, to find bio-inclusions with a non-invasive approach. In this paper, is presented a preliminary work for testing a homemade measurement system for local characterization of plants, to determine the necessary sensitivity to study the changes induced by modification of the bio-sample over the time due to an aging process. Preliminary experimental results, showing the capabilities of the developed system, are shown and discussed. In particular, changes in the order of few ohms can be recorded using an impedance measurement, using both real …