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Leaf analysis (also called tissue analysis or foliar anaylsis) is an excellent means of monitoring plant nutrient levels. With perennial fruit crops, leaf analysis is even better than soil tests for determining an optimal fertilization program. While soil tests reveal the quantity of certain nutrients in the soil, leaf analysis shows exactly what the plant has succeeded in taking up. However, soil tests are necessary for determining soil pH and thus lime (or sulfur) recommendations. If nutritional problems are suspected in a given planting, it's a good idea to take both leaf and soil tests.

Leaf analysis is helpful for detecting nutrient deficiencies in perennial fruits before they affect plant health or yield. It is important to sample fully mature leaves before they begin to senesce late in the season. Follow specific instructions for ideal sampling dates each crop. Do not submit plant tissue that has disease, spray residue or oter potential contaminants. 

Strawberry samples should be taken from the first fully-expanded leaves after renovation, about July 15 to August 15. Raspberry samples should be leaves from non-fruiting canes taken between August 1 and 20. Blueberry samples should be leaves taken during the first week of harvest, from July 15 to August 15. 

Place samples in sealed paper bags, clearly labeled with field or block names, ad mail promptly. Options for tissue analysis include (which provides Cornell fruit recommendations), testing Lab, testing lab, and analytical lab.

Here are the tables from the New England Small Fruit Management Guide showing desired ranges of nutrient concentrations in small fruits. Vermont growers can ask the lab to send me a copy of their test results, and then contact me for specific fertilizer recommendations: vernon.grubinger@uvm.edu.