Fertilization

It is relatively easy to burn the roots of kiwivines, so apply fertilizer cautiously. The following recommendations are based on our experiences in the Pacific Northwest.

Fertilize young kiwifruit vines monthly with small amounts of nitrogen (N). Ammonium nitrate and urea are good sources of nitrogen for kiwifruit.

In the first year, apply no more than 0.4 oz of actual N per plant per month in May, June, and July (12 lb actual N per acre for 160 plants per acre). Spread the nitrogen in a circle 6 to 12 inches from the base of the trunk.

In the year after planting, apply 0.8 oz of N per plant per month in April, May, June, and July (32 lb N per acre). Spread the fertilizer in a ring about 12 to 36 inches from the trunk.

Fertilize third- and fourth-year plants with 2 to 3 oz of actual N every other month from March through July (60 to 90 lb N per acre). Apply the fertilizer as a broadcast band under the vine canopy. You may liquid-feed nitrogen to young plants on a 2-week to monthly interval instead of using granular fertilizer.

Do not fertilize young plants with liquid or granular forms of nitrogen later than July. Late fertilization forces late vegetative growth, which is very sensitive to cold injury. Once plants bear fruit, the crop load tends to suppress late vegetative growth and reduce the risk of fall frost damage.

Other nutrients may be added in spring either foliarly or to the soil surface. Base applications on nutrient needs/analysis. Kiwifruit vines tend to take up a considerable amount of phosphorus (P) and potassium (K). Test soil for P and K prior to planting, and incorporate nutrients preplant if necessary.

DO NOT use fertilizer containing chloride (i.e., KCl), as kiwivines are very sensitive to chloride.

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