A plant growth measurement and prediction system uses drone-captured images to measure the current growth of particular plant species and/or to predict future growth of the plant species. For example, the system instructs a drone to fly along a flight path and capture images of the land below. The captured images may include both thermographic images and high-resolution images. The system processes the images to create an orthomosaic image of the land, where each pixel in the orthomosaic image is associated with a brightness temperature. The system then uses plant species to brightness temperature mappings and the orthomosaic image to identify current plant growth. The system generates a diagnostic model using the orthomosaic image to then predict future plant growth.