Sampling Guide
Plant Tissue Sampling Instructions
Sampling the right plant part at the right stage gives the clearest picture of crop nutrient status. Follow these general guidelines.
Step-by-Step
- Sample the recommended plant part. For most crops, collect the most recently matured leaves (the youngest fully developed leaves). For petiole testing, collect the petiole — the stalk that joins the leaf blade to the stem.
- Collect enough plants. Gather the same plant part from 20–30 representative plants across the area to form one composite sample.
- Match the growth stage. Nutrient sufficiency ranges are tied to crop stage, so sample at the stage recommended for your crop and keep it consistent across the sample.
- Keep tissue clean. Avoid dusty, diseased, insect-damaged, or dead tissue. If leaves are dusty or soil-splashed, brush them off or rinse briefly in clean water and pat dry.
- Use a paper bag. Place the sample in a clean paper bag (not plastic) so it can breathe and avoid mold. Label it with your sample ID matching the Chain of Custody form.
- Keep cool and deliver quickly. Keep samples cool and out of direct sun, and deliver them to the lab as soon as possible.
Good Practice
- Sample uniform, healthy plants representative of the area.
- Pair tissue sampling with a soil sample for fuller context.
- Note the crop and growth stage on the form.
Avoid
- Diseased, stressed, or insect-damaged tissue.
- Sealing fresh tissue in plastic, which promotes mold.
- Mixing different crops, varieties, or growth stages.
The correct leaf, petiole, and growth stage vary by crop.
Contact us for crop-specific sampling protocols.