Portable meter to measure chlorophyll, nitrogen and water and methods

A device for determining chlorophyll content, comprising:

• a sample receiving area configured to accommodate a sample during testing;
• a light source positioned adjacent the sample receiving area and operable to subject a sample in the sample receiving area to at least three different wavelengths of light;
• a photodetector operatively arranged adjacent the sample receiving area and configured to detect responses to the at least three different wavelengths of light;
• and
• a microprocessor connected to the light source and to the photodetector, the microprocessor controlling the light source and the photodetector and calculating a chlorophyll value of a sample based on at least the responses to the at least three different wavelengths of light.

A method for determining chlorophyll content, comprising:

• providing a sample;
• subjecting the sample to light at multiple different wavelengths;
• detecting a response for each of the different wavelengths;
• determining a water content of the sample;
• calculating a chlorophyll content of the sample with a device for determining chlorophyll content based on the response for each of the different wavelengths and the determined water content of the sample.