This is the time of year when vineyard owners’ thoughts turn to frost. Spring frosts can severely damage vulnerable vine buds, even wiping out a whole crop if frosts come at the wrong time.
Frost has been an ever-present danger for many established wine regions across the world and methods have been developed to reduce the risk of frosts happening and to combat the impact when they do.
The relatively young British wine industry (with new entrants entering this expanding industry) doesn’t have the advantage of the generations of knowledge that many of these regions can call on, and there seems to be quite a bit of learning on the job with the risk of reinventing the wheel.
As frost is a regular risk for many British wine regions, there is much to learn from the frost mitigation techniques used in other countries.
Methods to avoid frost often need to be considered when vineyards are planted. For example, avoiding planting in frost pockets. Planting earlier budding varieties on slopes so any frosts flow down the slope and away from the vines, leaving flatter, more frost-prone land for later budding varieties.
Many older English vineyards were planted with later budding varieties from Germany. However, care needs to be taken as to the commerciality of the wines made from these lesser-known grapes. There is a reason that Chardonnay and Pinot Noir have overtaken these historic grape varieties in British vineyards.
Many British vineyards have been planted without the detailed weather and topographical analyses needed to minimise the risks from frost. Many were simply planted where land was available or as a hobby.
However, it isn’t always bad news. Valley Farm Vineyards in Suffolk which I visited recently is planted in a beautiful tranquil valley, which is also a frost pocket. However, it’s very coolness means that budding is naturally delayed. As happened in 2021, thus avoiding late frosts.
However, that can’t always be relied upon, particularly since climate change is bringing warm spring weather forwards, tricking vines into budding early, then hitting them with spring frosts into April and May.
Combating the impact of frosts
Fortunately, there are techniques to combat the impact of frosts when they occur. Some are best considered when vineyards are established or refurbished. For example, installing sprinklers for frost protection. Others can be utilised as required, like wind machines to keep the air moving, and candles and smudge pots placed between the vines to warm the air.
All come at a cost in terms of money and effort. Sprinkler systems have large upfront costs in terms of equipment and installation, with running-costs being electricity and water. Wind machines involve a large capital outlay, with electricity costs being the primary running cost.
Candles and smudge pots don’t require the upfront investment but are likely to be a more expensive option over the long term if frosts are a regular occurrence.
Environmental considerations include the pollution from smoky smudge pots and water availability for sprinkler systems.
Experiment: later winter pruning to delay bud burst beyond frost risk.
Valley Farm Vineyard is running a test this year, delaying pruning a row of Pinot Noir until after Easter and comparing the budding times with vines pruned in early March. It will be interesting to see the results.
As can be seen, there is a lot for vineyard owners and managers to consider. Consultancies can help with this of course. However, I believe that if the British wine industry is to compete effectively in the global wine market there is great value in working together to build the sort of industry knowledge that established regions benefit from.
With that in mind, it is good to see industry bodies like Wine GB working with their members to share experiences and build a knowledge-base tailored to Britain’s climate and topography.