Vermont orchards and vineyards: Plant tissue testing for fertility management

As the calendar flips to August, it’s time to wrap up field activities in preparation for harvest in Vermont orchards and vineyards.

Foliar nutrient analysis – It is the time in the growing season to collect leaf samples in apples and petioles in grapes for analysis. Apple leaf samples are usually collected between July 15 – Aug. 15. Grape petiole samples may be collected at bloom or veraison, and comparisons between years or blocks should be based on the same time of collection. Veraison samples are a couple of weeks out for most vineyards. Samples should be collected separately for each cultivar or block. For apples, collect 50 leaves from the middle of this years’ terminal growth- not too old nor too young- from throughout the block and the tree canopy. In each vineyard sample, a random collection of 75-100 petioles should be collected from throughout the planting. Petioles should be collected from the most recent fully expanded leaf on the shoot, not across from the fruit cluster as is collected for a bloom sample. Just remove the whole leaf and snip the petiole (the leaf ‘stem’) off with your pruners.

Gently wash each sample in water with a drop of dish detergent, then rinse fully and place in an open-top paper bag to dry. The best analytical lab for grape petiole analysis that will provide recommendation for next year’s nutrient inputs is Dairy One, which is associated with the Cornell Nutrient Analysis Laboratory. Video- Taking a Foliar Sample: Vineyards and Orchards Taking a Foliar Sample: Vineyards and Orchards (University of Minnesota)

The UVM Agriculture and Environmental Testing Lab can provide analysis, but at this time their output does not generate fertility recommendations. The following are potential options of labs for analysis. It is recommended that you contact the lab for instructions and costs before samples are sent. Plus, it is important to confirm that they will send recommendations along with the analysis.

(1) Dairy One:
(2) University of Maine Analytical Lab:

Where trade names or commercial products are used for identification, no discrimination is intended and no endorsement is implied. Always read the label before using any pesticide. The label is the legal document for the product use. Disregard any information in this message if it is in conflict with the label.

The UVM Tree Fruit and Viticulture Program is supported by the University of Vermont Agriculture Experiment Station, UVM Extension, USDA NIFA E-IPM Program, and USDA Risk Management Agency.

UVM Extension helps individuals and communities put research-based knowledge to work. University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or familial status.