Over the next several weeks and months leaves and petioles should be sampled in perennial crops. Leaf analysis can assist in evaluating this season's crop nutrition management and plan next season's program. The table below outlines sampling times, plant part to sample and number of leaves to submit for perennial fruit cropsfootnote 1.

Calendar dateCropPlant part sampledApproximate number to collect
Before July 1Strawberry fruitingFully expanded, recently matured leaf blade — discard petiole immediately50 blades throughout sampling area
July, last 2 weeks


Cherry, Montmorency



Mature mid-shoot leaves of current year growth at shoulder height from all sides of tree10 leaves from 10 representative trees
Late JulyRaspberryFully expanded leaves from fruiting cane100 leaves throughout sampling area
Late July-early AugustBlueberry, HighbushMature mid-shoot leaves of current year growth100 leaves throughout sampling area
Early AugustStrawberry non-fruitingFully expanded, recently matured leaf blade - discard petiole immediately50 blades throughout sampling area
Early SeptemberGrapesPetioles from mature leaves of fruiting canes. Remove from leaf immediately75-200 depending on variety size

Before you start sampling

  • The plant part sampled and stage of growth affects the interpretation of the results.
    For example, the table below shows the differences in some referenced critical ranges for wine grapes, Vitis vinifera, sampled at different growth stages and for different plant parts being sampled. Keeping records of cultivars sampled, timing of sample collection, and plant part sampled will help in building a historical reference.
 Whole leaves, opposite bunch cluster, early summerfootnote 2Petioles opposite basal flowers, full bloomfootnote 2Petioles from mature leaves of fruiting canesfootnote 1
Nitrogen, %
Phosphorus, %
Potassium, %

Sampling tips

  • Sample varieties or blocks separately that require different management practices.
  • If variable areas are large enough to fertilize separately, sample them separately. Match your leaf sampling to your soil sampling program
  • Avoid collecting damaged leaves or leaves from plants that appear abnormal.
  • Collect tissue samples in clearly labelled paper bags. Plant tissues will rot if stored in plastic bags.
  • Avoid contamination of the sample with soil. Even a small amount will cause the results to be invalid, especially for micronutrients.
  • Plants suspected of a nutrient deficiency should be sampled as soon as a problem appears. Take tissue samples from problem areas and submit them separately. Also collect and submit a non-affected plant from adjacent areas. Collect and submit soils sample from both areas as well.
  • Fresh samples should be delivered to the laboratory directly. If they cannot be sent immediately, they should be dried to prevent spoilage. Samples may be air dried as long as they are not contaminated by and dust or debris while drying. They can also be dried in an oven at 65°C or less.
  • For perennial crops, leaf analysis is an important complement to soil testing. Over the long term, it can tell you whether your soil fertility program is supplying adequate nutrients for optimum growth. It is also a useful tool for trouble shooting problems. If your soil tests show adequate nutrient levels, deficiencies indicated by a leaf test may give clues to other problems restricting nutrient uptake.

Where to send samples

Several Ontario commercial soil testing laboratories can provide you with leaf analysis. Their contact information can be found at Soil, leaf and petiole tissue, and forages and feed testing labs.