This paper considers the range of techniques now available to assess the physiological competence of microplants. We emphasise in particular the usefulness of remote sensing techniques to assess the functioning of stomata and recommend the use of the micropressure probe and the root probe to quantify the effects of culture techniques on plant water relations and root water flux, respectively. A number of analytical techniques is available to probe photosynthetic competence and these are reviewed but again, a remote sensing technique is recommended as a simple means of assessing photosynthetic performance.