Written by Joe Connell, Butte County Farm Advisor Leaf analysis for the full range of nutrients is best done in July when nutrient levels in leaf tissue are stabilized. Published July critical values established for almond by U.C. researchers can help guide you in your fertilization practice.  Analysis can reveal specific nutrient deficiencies or can alert you to developing trends when results are compared from one year to another.  Keeping trees in the adequate zone for nitrogen can save on fertilizer costs by helping to avoid over fertilization.