Rathfinny Wine Estate

Phenology – What goes around comes around

With the success of our launch at the end of April, the pressure is well and truly on to carry on producing the best grapes for our Sussex Sparkling. As part of the U.K wine industry, we find ourselves at a very fortunate standpoint in comparison to some of our European counterparts in the face of climate change. Even though research points to more unpredictable weather conditions in the U.K, we are also eagerly anticipating higher temperatures and less rain during the growing season (emphasis on eagerly) whilst southern Europe is facing short-term realities of severe drought conditions, extreme heat and ultimately, the inability to grow or produce certain varieties and wine styles. But what is phenology and what does it have to do with this?

Phenology is the study of the seasonal stages of plant and animal life in relation to climate. The same grapevine processes happen every year but needless to say, the timing or duration can vary significantly which is why we go out and track each stage – the major three for us are bud burst, flowering and veraison. You’ll often hear viticulturists discussing whether the season is early or late, but why does that matter?

Bud burst signals the start of the growing season and it is predicted that this initial stage will get earlier and earlier as time goes on. On the surface, this is good for us – it means we can harvest earlier and our grapevines will start to ripen the fruit in the warmest months with the best weather. 

That’s great I hear you say! Surely an earlier growing season means more hang time for our grapes, allowing the sugars to rise and the acids to fall leading to a more balanced wine. While that is true, it also means we are more susceptible to spring frosts like the two severe events witnessed in 2017. We were lucky to escape these and we’re still not out of the woods this year, but if young shoots are killed off not only would we lose large proportions of our crop, our vines would also have to start from scratch by pushing out secondary buds which are less fruitful. In addition to using a lot of valuable energy, the growing season is shortened which is really detrimental in marginal climates like the U.K. Every day counts because we harvest at the absolute precipice of the season– shortly before leaf fall – and often we cannot wait any longer to bring in our fruit. Not only are we concerned about this from a fruit quality perspective, later harvests don’t give our vines much time to store up energy reserves before they go dormant in preparation for spring the following year. In turn, this could have negative effects on the amount of fruit we produce the next season – again showing the difficulty of farming a perennial plant…

This year, the start of bud burst was roughly two weeks later than in 2017 however, the ‘mini-heatwave’ helped our vines progress through this stage very quickly which means we have just about caught up. Knowing this allows us to tailor our vineyard operations whilst building a record of the estate and helping us to assess the risk of bad weather when it happens. The ability to drill down into a catalogue of data that is site, variety and clone specific is the ultimate goal as this will provide us with a powerful insight into our vineyard that will give us an edge when thinking about how to mitigate any negative effects of the more erratic weather conditions predicted in the future. At the moment we’re still finding our stride, but as the site grows the importance of data-driven decision making will become more and more apparent. Whether that’s choosing clones that ripen earlier or later in the season, investing in frost protection for certain areas or aiding decisions on when and which crop protectants to apply, we want to be ahead of any potential disasters so we can carry on making wine for you to enjoy.



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