The Importance of Post Harvest

Wednesday, September 7, 2016

Many California wine and grape growers are heading into the home stretch of this year’s harvest. During Autumn, as with most deciduous plants, nutrients are withdrawn into the plants from leaves prior to leaf fall. Post harvest is a critical period to apply soil based and foliar fertilizers as the vines are actively translocating nutrients from the leaves to the canes and the trunk of the vines to store these elements as a carbohydrate source. Vines also require multi trace elements for carbohydrate assimilation and the metabolic reactions which occur when the vines are in the carbohydrate storing mode.

Not only is overall nutrition important, but irrigation management is also critical. Dry soils after harvest inhibit the second flush of root growth and cause early leaf fall thus limiting the build-up of carbohydrate and fertilizer reserves in the wood of the vines which is essential for bud and shoot growth during early spring.

Existing research into vine nutrition has indicated that major gains can be made in fruit quality by having a greater understanding of the uptake of nutrients by the vine. Soil chemistry is complex and the addition of nutrients is affected by existing levels as well as the nutrients that we are adding. For instance, high phosphate levels may reduce zinc uptake, additional of nitrogen can accentuate copper deficiencies, and high calcium levels can decrease boron and iron uptake.

balance of soil and foliar products and a balance of elements is the best approach at the end of the season in order to best replenish the lost reserves of the vines before dormancy and improve cold tolerances in the springtime. Andaman Ag offers a large array of biological fertilizers composed of complex macronutrients and micronutrients applied via soil or foliar (Ecotech), high metabolite compost teas (Sustainable Growing Solutions) and humic based compounds (WISEarth). We also offer exceptional separate post harvest micronutrients – Boron, Zinc, Manganese and Iron products (NutriAg) that are ideal foliar applications given these elements have limited availability through the soil.