Leaf area meter in your smartphone - this is Petiole.LeafArea. Do not waste money for expensive equipment, save time not using ImageJ and grid.
Solution is right in your pocket.

Open the door to the world of agriculture research and agriculture chemistry. Measure individual leaf area, get total leaf area , save data and see comparisons. Leaf Area Index (LAI) or Specific Leaf Area (SLA) - this app helps with both.
Soybean, corn, wheat, potato, coffee, pepper, olives, vine leaves or cannabis (marijuana) - Petiole.LeafArea measures most of the plants leafs in just a tap.
Petiole.LeafArea can help every agronomist, seed selector, plant breeder, biologist, ecologist, agri chemist and many more people who are doing agriculture research, testing fertilisers, biopesticides or any other chemicals for crops. This app helps to monitor plant health, choose plant phenotype for screening, and understand plant stress faster.
Make productive experiments and effective decisions for your agriculture business.

Download the calibration pad for measurements here: http://petioleapp.com/Petiole.LeafArea-Calibration-Pad.pdf and print it out in a plain white paper sheet. Now it is ready to use! Have accurate leaf area measurements and good luck with your scientific projects.