Maximize Fruit Quality with Targeted Applications of Potassium

Potassium (K) is one of the most essential nutrients associated with vine production and is commonly the most misapplied. In plants, K is involved in many essential functions listed below.

• Regulates water pressure in plant cells, affecting cell extension, gas exchange, and movement of leaves in response to light
• Activates enzymes that help facilitate chemical reactions
• Synthesizes proteins
• Adjusts pH within plant cells
• Increases carbon dioxide fixation during photosynthesis
• Transports chemical compounds
• Balances electrical charges in various parts of cells

Potassium is readily available in most soils. However, vines usually cannot take up enough K to satisfy crop requirements during peak demand. This spike in demand starts just before fruit set and continues through sizing. Since K moves into the roots through diffusion (very short distances in the soil), drought, deficit irrigation, high salinity, sandy soils and high soil levels of calcium and magnesium can adversely affect K uptake. Lack of K early in fruit development can lead to smaller fruit, lower TSS/sugars in grapes, uneven ripening and poor color development. K deficiencies in the leaf result in necrosis (cell death) of leaf tips and margins, beginning on older leaves. This causes increased susceptibility to water stress and plant pathogens as well. The key concept in K fertility is getting readily-available K into the vine early and often, so the plant has time to metabolize it and actively translocate carbohydrates to the fruit.

Fortunately, Helena has the tools to mitigate deficiencies and effectively maximize the K you apply. A two-pronged program (soil and foliar K) efficiently delivers optimum K to the vines in a timely fashion.

In the soil-applied portion of the program, rely on Nucleus® 0-0-21 or Nucleus 0-0-15. The Nucleus K line utilizing Konduit™ Formulation Technology increases the solubility and mobility of K in the soil (a major challenge for conventional K fertilizers). This package overcomes fertilizer inefficiencies and K fixation by soil colloids. Another benefit is unsurpassed compatibility with other liquid fertilizers, making it an ideal blending partner.

The cornerstone of our foliar program is a tank mix of K-Leaf® Versa and Utilize® PK. Foliar-applied K can be difficult for vines to absorb, especially formulations which utilize flowable or micronized suspensions. With K-Leaf Versa and Utilize PK, you get true liquids designed for rapid uptake and metabolism.

K-Leaf Versa is a concentrated 0-0-29 solution utilizing ENC® Formulation Technology with a complete micronutrient package. It is compatible with most pesticides and other foliar nutritional products. Utilize PK is a nutrient solution, formulated by Goëmar, which can speed up plant metabolic processes to help vines acquire and utilize higher levels of soil and foliar nutrients. This powerful combination drives applied K where it is needed most – in the leaves. There, it is metabolized and boosts carbohydrate translocation to the fruit. This results in the vines receiving the K they require during the most critical times of fruit development.

With a Grape Wise plan tailored to your vineyard, Helena consultants will provide agronomic information and expert recommendations throughout the growing season. Ensure your vines are well fed for maximum quality and yields. Contact your local Helena representative to develop your Grape Wise plan today.

- Paul Crout, CCA, PCA, Helena Product Manager