March in the Douro was certainly interesting enough because there was plenty of the variation that is so typical of the spring to keep everyone entertained. The month got off to a bright, sunny and warm start although the clear skies ensured that the nights were still very cold. This produced a bit of a scare when we woke up to a heavy frost on the morning of the 7th. The concern stemmed from the fact that younger vines (before they enter into production) characteristically have earlier budburst than adult vines. By this date there were already young vineyards with two or three leaves unrolled but fortunately the frost was not intense enough to damage the new shoots. It is fair to say that at this time of the year frosts usually only occur on the cooler high ground, where budburst of course comes later on. However, if budburst progresses uphill faster than the risk of freezing temperatures tails off for the respective altitude, the possibility remains of a potentially dangerous combination occurring whereby frosts and green plant tissue are present simultaneously. Frost damage of the primary shoots has serious implications for yield because, although the vines would still be able to burst again from the secondary buds, these back-up shoots are noticeably less fertile.
By the second week there were severe storms striking all along the Atlantic coast of Europe and causing some serious destruction. This was accompanied by plenty of rain in Porto but unfortunately the wet weather had virtually no penetration inland as far as the vineyards where basically dry weather persisted. All that the Douro experienced was generally fair, typical spring weather, albeit changeable. There were fast moving clouds, blustery conditions and a couple of wet days but nothing significant. Things then appeared to get much worse (or better, if you like, considering the drought) as looming black clouds began to build up and sudden squalls flashed down from extremely threatening skies. Disappointingly, however, the gusts normally ended up blowing away the clouds more often than not and thus these storms brewed ominously but hardly ever delivered the downpours that they promised. Although the shoots on the vines were at a fragile stage, they were also very short so the high winds that we experienced for much of the middle of the month didn’t do any damage.
The winds continued over a very early Easter season and down in Porto it got bad enough for some hail to make an appearance, coinciding with what was a white Easter for much of the UK. There were even unconfirmed stories of snowfalls in the Alentejo doing the rounds.
In Pinhão the month brought 22 mm of rain overall, although this is less than half of the average of 51 mm. We have now had just 165 mm in total for the first three months of the year. As has already been mentioned, there was no consistent pattern to the rain, just a few light spots scattered almost randomly throughout the month, but admittedly none fell during the first week or so.
In terms of temperatures, the average value was 12.0º C – not noticeably different from the mean of 12.3º. There were, however, considerable fluctuations as the uncertainties of spring often bring, including eight days into the twenties and nine days below 5º.
In terms of vineyard activities, the work was again very much dictated by the state of the vines and the weather. It is perhaps curious to note that a surprising number of grape growers were still finishing off the pruning at the start of March. The fear of frost described earlier might explain this, since later pruning delays budburst and thus reduces the risk to the vines.
The interesting part of the Spring season though is, of course, the start of a new vegetative cycle, and budburst was truly upon us early on in the month. This year’s average date was March 17th, two days later than last year but still somewhat earlier than usual. The date is not hugely meaningful in itself since budburst is actually determined by a whole combination of factors, some obvious and others less so. They include the preceding climatic conditions, location and altitude, casta, the age of the vine and its vigour and so on. There might be a month’s difference between the bursting of the first buds in the Douro and the last, but this figure is a fair approximation based on a representative vineyard that we have now been following for several years.
With budburst out of the way the one thing we can be sure of is that the flowers that give rise to this year’s crop of grapes will soon become visible on the new shoots, and once again the endless ill-informed speculation about the size of the harvest will ring prematurely through the Douro for want of something better to talk about. Elsewhere the majority of the new plantings were entering their final stage, if not already finished, and we were busy opening up small circular depressions at the foot of each new rootling to maximise the rainfall it captures and help us with the watering.