As we get closer to grape harvest, many of you have been asking us about options for increasing the maturation of vineyard blocks. The question is, how can you accelerate improvements in color, sugar and phenolic levels?
The last 30-40 days prior to harvest is when sugar content begins to ramp up in the fruit. After the peak of sugar content, further increases in brix are mostly due to berry desiccation or moisture loss. Sugar-to-acid ratios start to decline as well. This may be acceptable in wine grapes but not table grapes.
At this moment in time a rev of the soil biology can help the vine process nutrients and trace elements faster and more efficiently. A reasonable option in terms of cost and performance is to apply compost teas like our MetaGrow ST compost tea via fertigation.
Compost teas help vines build sugars during this sugar loading period by reducing vine stress. Stressed plants produce less sugar as they actually shut down transpiration for a few hours, typically late in the day, during peak stress events like max fruit load or heat stress.
The active soil microbes in compost tea are well documented to increase a plants’ tolerance to stress. The microbe metabolites in compost tea also include plant growth regulators, amino acids, enzymes, and other complex organic compounds like flavonoids, which are immediately plant available and the building blocks for fruit flavor and color.
We also carry a product called CropBioLife, a natural flavonoid produced from the rind of bitter oranges. All plants produce and exudate flavonoids, which are secondary metabolites responsible for disease resistance, fruit color and flavor. The thinking here is that if we can supplement the naturally occurring flavonoids in a plant, we can accelerate and enhance color, flavor and phenolics. In addition, CropBioLife is a synergist for nutrients and other materials like fungicides, helping to improve product performance when used in combination. CropBioLife is applied as foliar spray.