Frost – What Next? – In association with WineGB
Wine producing regions in the Northern Hemisphere are particularly exposed to the risk of early season frost events when the advancement of budburst occurs, in response to increased spring air temperatures.
Freezing and damage to cells in buds and young shoots can put the current season’s crop at risk but also, because of the perennial nature of grapevines, the productivity of vines in the following season. The degree of damage will depend on the phenological stage of the vine, the degree of frost severity (critical temperature) and the frost event length.
There are two main types of frost events, which can damage vines:
- Advection frosts: large cold air masses. Signified by freezing cold winds / air movement, commonly from the north.
- Radiation frosts: formed due to cooling from ground energy loss. Signified by clear, cold nights with little or no wind, and the formation of an inversion layer (a layer of the atmosphere in which temperature increases with height). These can occur on a macro or micro level.
This year (2020), we have seen both advection and radiation frosts in England in the early [critical] part of the growing season (11th – 15th May). On some nights both types of frost types occurred one after the other, making management of conditions difficult.
The ability to protect vineyards from frost events is fundamental to a profitable vineyard enterprise. However, managing frost risk requires a case by case approach to determine risk levels and optimal protection solutions and strategies because every vineyard has somewhat different topographies, soil types and exposure risks.
Vineyards should therefore implement a vineyard frost risk mitigation strategy and we’ve set out the key steps for this below.
How to prepare a vineyard frost risk mitigation strategy:
- Obtain in-site or local historic (10-year) temperature data from March to May (available from VineMAP). If not installed, place weather sensors which provide valuable data and frost warnings. This data can aid the frost risk mitigation plan going forward.
- Identify frost sensitive areas in the vineyard i.e. where cold air accumulates or channels, and map prior vineyard damage patterns.
- Design an operational vineyard management to plan for spring frost, for example:
- On frost sensitive sites, late prune to delay bud break and/or leave sacrificial canes.
- Ensure any inter-row and headland ground cover is mown or kept to a minimum.
- Encourage firm inter-row soils and uncultivated ground to reduce heat loss.
- Where possible remove or thin any barriers to cold air flow (cold air flows down slope), such as hedges, undergrowth or equipment.
- Evaluate and determine the most suitable frost protection equipment for the vineyard to ensure delivery prior to spring. Large frost protection equipment often has a 3-4-month lead time.
- Determine how specific frost risk events will be managed. Document who will do what and which equipment will be used.
- Document the vineyard frost risk mitigation plan & communicate to any team members before the start of the new year and again in March. Ensure to update the strategy annually.
Effectively fighting early season frost risk is not straight forward and getting it right is key. At Vinescapes, we have spent the last 10 years undertaking scientific research and advising clients on the best way to mitigate this significant issue.
If you would like our help and advice or for us to undertake a frost risk and mitigation audit for your vineyard, please let us know. We are offering a 5% discount on our frost risk services until the end of September.
Please visit our product page if you would like to know more about the frost protection products available.