Frost season is here and many Mendocino County farmers are in shock with the early arrival of the serious risk of damage to their grapevines.
Normally grapevines awake from their winter dormancy around mid-March. Some varietals are earlier and some later. This year, the warm winter and long stretches of dry weather have confused the biological clock inside each grapevine. Many vineyards have started to “wake up” with delicate buds opening and the first leaves of 2015 appearing. This “budbreak” is about 3 weeks ahead of schedule.
A cause for celebration, right? Unfortunately, the threat of frost damage at this time of year is extremely high and farmers prefer that the grapevines stay dormant, and relatively safe from frost, as long as possible.
This Monday morning temperatures fell below 32 degrees Fahrenheit in many parts of Anderson Valley and Potter Valley. About a dozen vineyards responded by activating sprinklers systems or wind machines to mitigate the risk of damage to the green and tender new growth.
Joe Webb, President of the Anderson Valley Winegrowers Association stated “Another record breaking early start to the growing and frost season is not what we had hoped for. We can only hope for some more storms to lower day time temperatures, increase nighttime lows and recharge our storage ponds.”
For vineyards that use sprinklers for frost protection the worry is that the ponds – which are thankfully full – won’t hold enough water for a large number of frost events. And while vineyards that use wind machines don’t have to worry about “running out of wind”, they are concerned about extra use because of the noise generated by the wind machines. One Boonville resident has filed a lawsuit against his vineyard neighbors based on the noise and challenged the Right to Farm Ordinance.
Though wind machines have been in use in vineyards for decades, several vineyards in Anderson Valley have added this technique to their farming practices during the recent drought as a water conservation tool. In an effort to minimize the noise impacts as well as remain good stewards of our resources, the Anderson Valley Winegrowers Association (AVWA) has issued a set of Best Management Practices (BMP) to which all regional vineyards are expected to comply. The BMPs cover topics like lowering the temperature settings at which the units start, proper maintenance and monitoring ambient temperature and humidity.
The group also launched a noise hotline in 2014 (phone number is 707-941-7441) to help identify the regions most impacted by noise. In addition, vineyards have created a frost notification system, so residents can receive the same advanced warning of frost conditions that vineyard managers receive.
Arnaud Weyrich from Roederer Estate points out that bud break varies by location: “Both location and altitude on the Valley floor affect the timing of breakbreak. Some of our Deep End vineyards show 5% budbreak but our Philo vineyards have yet to start.” One grower on Signal Ridge reports his vines are already at 90% budbreak.
About AVWA: The Anderson Valley Winegrowers Association operates with the goal of supporting the region’s grape growers and wineries, as well as promoting the region’s wines. In addition to acting as a resource for its members, the association aims to better its community through donations. To-date, more than $250,000 – raised at the association’s events – has been given to local charities. The AVWA has approximately 120 members.
About MWI: Mendocino WineGrowers, Inc (MWI) is a voluntary group of winegrowers and vintners created in fall of 2012 to promote the reputation of the grapes and wines of Mendocino. Mendocino County is a unique collection of heritage vineyards, organic pioneers, name-brand wineries, and family businesses. The region is home to 8 recognizedViticultural Areas with 550 vineyards properties and more than 100 winery businesses.
