A method of quantifying growing plants in an area is disclosed wherein the area is scanned with an active light sensor which provides a data signal when a plant is present that is distinct from the data signal provided when a plant is not present. The data signal is analyzed to determine at least plant population densities, the spacing of plants, the number of emerged plants versus planted seeds, the size of the area that has unproductive plants or an estimate economic and/or yield loss. Overlapping sample areas can be used to improve the accurate quantification of plants.
