Foothill Grape Day 2018 will be held Thursday, March 29 from 7:30 a.m.to 3:00 p.m. at the Amador County Fairgrounds in Pokerville Hall. This year's theme is "Vine Balance", which I think of as the sweet spot in growing a particular block of grapes. This occurs when the vegetative canopy and crop load can be sustained and provides the desired grape quality.
Vine balance is more than an academic concept. It is the foundation for making management decisions from planting time (rootstock choice, vine spacing, trellising type) to seasonal (irrigation, fertilizer, cover crop) and cultural options (canopy management, crop thinning) to harvest (grape quality and yield). It requires an in-depth understanding of your vineyard site
Assessing your vines during pruning, and collecting pruning weights, provides you with valuable information to assess your vine balance.
and the variety and rootstock characteristics. It also considers weather patterns, for example, what amount of rainfall do you have going into this season, and what is your soil's water holding capacity for that rainfall? What was the season like last year? Were the vines overly stressed due to lack of water (which would affect wood and bud renewal)? To help you determine the vine's balance, you may want to collect some data from your own vineyard blocks: pruning weight and cluster weight information can assist you in assessing how balanced your vines are.
You don't need a digital scale like this one to measure your fruit weight.
To lead the Grape Day discussion on Vine Balance, I've invited the best speakers I know of to address this topic: veteran UCCE Viticulture Advisors from around the state. Mark Battany, UCCE San Luis Obispo, will discuss below ground factors influencing vine balance. Mark has a background in soil science and is known as a bit of a "techie" in our group; he created the infamous "Paso Panel" to help measure canopy light interception and has done quite a lot of work on groundwater issues in his part of the state. Larry Bettiga, UCCE Monterey, will share basic pruning and training principles for balanced vines. Wondering when cane pruning should be implemented? How to know how many buds to leave on a spur pruned vine? Larry
Understanding your soil is a key to achieving vine balance.
has years of experience conducting trials on the Central Coast. Rhonda Smith, UCCE Sonoma, will discuss canopy management. This includes leafing and shoot thinning, row direction and how that affects the canopy and fruit development. Rhonda is a serious viticulturalist, who carefully considers the consequences of management decisions. George Zhuang, UCCE Fresno, is the newest viticulture advisor on our team. George has recently completed some trials of crop load on young pinot grigio vines in his area and will share the results of what can happen when you crop too much, too soon. Glenn McGourty, UCCE Mendocino, is a perennial favorite speaker for Grape Day because of his love of wine and interesting wine varieties. Who better to discuss the inherent variety characteristics affecting vine balance? Kaan Kurtural, our UCDavis Viticulture Specialist, has quickly established himself as a workhorse leader in conducting studies pertinent to today's vineyard. He will discuss affects on fruit quality-the end result of vine balance management strategies.
Vine balance starts with good vineyard design.
Also, as a special treat, Yorba Wines and Shake Ridge Ranch vineyard manager Ann Kraemer has agreed to come and share her techniques for estimating yield and adjusting fruit load. Ann is a knowledgeable and articulate speaker and I'm grateful to have a grower give practical advise.
All are welcome to attend Foothill Grape Day. To register, please go to: http://cecentralsierra.ucanr.edu/Agriculture/Viticulture/Foothill_Grape_Day_2018/
or contact Robin Cleveland, office assistant extraordinaire, at 530-621-5528, to sign up! I hope to see you there!
UCCE Viticulture Advisors during a recent trip to Chile. Pictured are (left to right) Jeff Baldwin, Lynn Wunderlich, Mark Battany, Larry Bettiga, Glenn McGourty, and Carmen Gispert.