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Cornell Fruit Resources: Berries

Resources for Commercial Berry Growers

Time for leaf sampling: July 21 berry update

With harvest season in full swing for raspberries, blueberries and currants/gooseberries, the main issue is staying on top of SWD sprays. Late strawberries are still being renovated. The other significant berry activity is leaf/tissue sampling, which should happen in the next few weeks. It’s easy to miss in the crush of harvest, but leaf sampling is an important step in understanding and managing berry nutrition. If you haven’t taken a soil sample in a few years, it’s never a bad idea to send some soil in for evaluation as well – it can really help direct appropriate actions to take.

Foliar Leaf Sampling – Late July Through Early August is the Target Time
by Laura McDermott, CCE ENYCHP

One of the best ways to monitor small fruit nutritional status is to do regular foliar testing. This allows growers to monitor performance over many seasons, and to provide individualized fertilizer programs where necessary. Soil tests provide a baseline, but the foliar tests are the ‘dietary plan’.

Timing is everything. Late July to mid-August allows most of the fruit plants to finish their spring growth, but it’s before the plant starts to move nutrients to the roots and crown in preparation for dormancy. Make sure also to gather a representative sample. The leaves should be distributed from plants throughout the field. If there is a problem area it would be great to do a broad field test – and then a targeted sample from leaves gathered from low vigor plants.

Wash dirt and spray residue off collected tissue using distilled water if possible. Blot off excess water, place tissue in a paper bag, allow tissue to air dry and then send to: Agro-One, 730 Warren Rd., Ithaca, NY 14850. For more information about this process, plus the correct forms and testing kits to include with submission, visit The cost is ~$27/sample.

Strawberries: Collect a minimum of 30 trifoliate leaves that are fully expanded after renovation in July or August. Day Neutral strawberries can be sampled at any time, but you should note the stage of bearing for them. Also, use a lab that can definitely give me results for this atypical crop.

Raspberries: For floricane varieties, collect 30 of the newest fully expanded trifoliate leaves from primocanes in early August. For fall raspberries (primocane varieties), sampling timing maybe a little tricky; and it is good to have soil analysis that is not less than two years old to compliment the leaf analysis. For example – foliar analysis in an early fruiting year showed low Potassium; soil levels were adequate. Probable explanation – fruit acting as a sink for foliar potassium.

Blueberries: Collect 30-50 newly expanded leaves from well-exposed branches in late July or early August. Blueberries often have 2 flushes of growth during season. Leaves for analysis should be fully expanded new growth from 1st flush, not second. Foliar analysis in new blueberry plantings may be beneficial but sometimes produce rather erratic results. This is attributed to the need for 4-5 years to pass after planting for plants to settle down and juvenile growth spurts to be over. Age usually calculated from when plants go in the ground; transplant age not necessarily included in calculation in this respect (i.e. 3 year old transplants, planted 3 years probably still in juvenile growth spurt.)

Currants and Gooseberries: Collect 30-50 newly expanded leaves from well-exposed branches in late July.

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