Adapted from Christoph Kessel – Nutrition (Horticulture) – Former Program Lead/OMAF and MRA, updated by Lydia Balogh (summer student) and Kathryn Carter, Erica Pate and Amanda Green (OMAFRA)
Table of Contents
Conducting Tissue Sampling
Mid- to late- summer is the ideal time to take leaf and petiole samples from perennial crops. Analysis of leaves and petioles allow growers to understand the nutrition of their crops, which can help in making informed decisions on fertilizer rates that can improve this season and next years’ crop. The table below gives an outline of sampling time for perennial fruit crops, what part of the plant needs to be sampled for analysis, and how much leaf tissue should be collected per sample.1
Calendar date | Crop | Plant part sampled | Approximate number to collect |
July, last 2 weeks | Apple Cherry, Montmorency Peach Pear | Mature mid-shoot leaves of current year growth at shoulder height from all sides of tree | 10 leaves from 10 representative trees (100 leaves total throughout sampling area) |
Late July | Raspberry | Fully expanded leaves from fruiting cane | 100 leaves throughout sampling area |
Late July-early August | Blueberry, Highbush | Mature mid-shoot leaves of current year growth | 100 leaves throughout sampling area |
June | Strawberry, fruiting | Fully expanded, recently matured leaf blade- discard petiole immediately | 50 leaves throughout sampling area |
Early August | Strawberry, non-fruiting | Fully expanded, recently matured leaf blade- discard petiole immediately | 50 blades throughout sampling area |
Early September | Grapes | Petioles from mature leaves of fruiting canes. Remove from leaf immediately | 75-200 depending on variety size |
Interpreting Laboratory Analysis Results
The stage of growth at sampling affects the interpretation of the analysis results. For example, the table below shows how referenced critical ranges for wine grapes, Vitis vinifera change depending on the timing of sampling and the plant parts sampled.
Whole leaves, opposite bunch cluster, early summer¹ | Petioles opposite basal flowers, full bloom¹ | Petioles from mature leaves of fruiting canes² | |
Nitrogen, % | 2.0-3.0 | 1.7-3.0 | 0.8-1.4 |
Phosphorus, % | 0.3-0.4 | 0.15-0.5 | 0.15-0.4 |
Potassium, % | 1.3-1.4 | 1.5-2.0 | 1.2-2.3 |
²OMAFRA Fruit Production Recommendations, Publication 360 2010-2011
Growers should keep records of cultivars sampled, timing of sample collection, growth stage of sampled plant, and plant parts sampled for future reference.
A complete list of the foliar nutrient sufficiency range for fruit crops (apple, berry, grape, tender fruit) can be found at: Table 3. Nutrient Concentration Sufficiency Ranges for Fruit Crops
Additional Sampling Information:
- Sample varieties or blocks separately if they require different management practices.
- Leaf sampling should match your soil sampling program. If variable areas are large enough to fertilize separately, they should also be sampled separately.
- Avoid collecting abnormal, damaged, or sick leaves as samples.
- Collect samples in clearly labelled paper bags and send for analysis quickly to prevent plant tissue rot.
- Fresh samples should be delivered to the laboratory directly. If they cannot be sent immediately, dry them to prevent spoilage. Samples may be air dried but avoid contamination with dust and debris while drying. They can also be dried in an oven at 65°C or less, or with a dehydrator household appliance.
- Avoid contamination of the sample with soil. Even a small amount can cause the results to be invalid, especially for micronutrients.
- For plants suspected of nutrient deficiency, take samples as soon as the problem appears. Take tissue samples from problem areas and submit separately from the rest of the sampling area. Also collect and submit a non-affected plant from nearby areas. Collect and submit soil samples from both areas as well.
- For perennial crops, leaf analysis should go alongside soil testing. Over time, results from these tests can show if soil fertility programs are supplying adequate nutrients for optimal growth. Results are also a tool for trouble-shooting problems. If soil tests show adequate nutrient levels, deficiencies shown in leaf analysis may give clues to other problems restricting nutrient uptake.
Where to Send Samples:
Several Ontario commercial testing laboratories can provide you with leaf analysis. Their contact information can be found on the OMAFRA website. For additional information assessing nutrient needs in fruit crops refer to Soil Management, Fertilizer Use, Crop Nutrition and Cover Crops for Fruit Production.