Bi-weekly tissue sampling recommended for North Carolina strawberries

This winter has been unseasonably warm, and strawberries across most of North Carolina are ahead of schedule. The North Carolina Department of Agriculture and Consumer Services recommends that growers in the Piedmont and Coastal Plain start their tissue-sampling program right away.

Submitting samples every two weeks from the first flush of growth in the spring until the end of the fruiting season is a proven best management practice.

Tissue analysis is a good way to monitor a crop’s nutrient needs and adjust fertilization precisely. Routine biweekly sampling makes it easy to identify potential problems and manage them before they can reduce yield. "Weather and pests may be somewhat unpredictable and remedial options are not always available, but there is no reason for yield to be compromised by a nutritional problem," said NCDA&CS Regional Agronomist Rick Morris.

The correct part of the plant to sample is the most recent mature leaf. This is the first fully expanded leaf from the growing point, usually about the fourth or fifth leaf from the growing point. Each sample should consist of 10 to 15 trifoliate leaf blades and petioles, collected randomly throughout a field. For accurate results, each sample should represent the same set of conditions — variety, growth stage, soil type and management practices.

When collecting tissue samples, be sure to detach petioles from leaves in the field. Samples handled this way will give a more accurate nutrient analysis. Leaf blades are analyzed for 11 essential plant nutrients plus sodium. Petioles, however, provide data on nitrate nitrogen concentration.

Put each sample (leaves and detached petioles) in a separate paper bag or envelope. Submit all samples along with a completed Plant Sample Information sheet and processing fee of $7 per sample. Envelopes for mailing tissue samples are available from the Agronomic Division office in Raleigh, your regional agronomist and some Cooperative Extension offices.

When filling out the information sheet, provide all pertinent data, including planting date, fertilization history, environmental conditions, appearance and strawberry variety. Be specific when describing any problems with appearance or growth. When trying to diagnose a problem, it is always good to submit samples from both “good” and “bad” plants for comparison.

Samples can be hand-delivered to the Agronomic Division laboratory in Raleigh or shipped according to the instructions on the information sheet. Analysis requires two business days.

Results are posted on the Agronomic Division Web site at, and growers receive reports in the mail a few days later. Reports include data on nutrient levels within samples, interpretative remarks and recommendations for corrective action, if necessary.

For more information about plant tissue analysis, call the Agronomic Division at 1-919-733-2655 or contact your NCDA&CS regional agronomist.

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