This April has been the frostiest on record in England. Like TS Elliot in ‘The Wasteland’ you may feel that ‘April is the cruelest month’. Certainly many vignerons would agree with you. Night after night, people fretted and stalked their vineyards trying to save this year’s crop. Once buds have burst they are vulnerable. They are full of water and very tender. As the temperature drops, they freeze. It is brutal cryosurgery. The buds die.
In previous years we have had bud burst here at Ambriel HQ on 1st April (and that’s no April fool). Luckily this year it was delayed. The vines seem to have sensed that it was not safe to emerge. Budburst is starting much later – which is a relief.
Unfortunately the frost has rampaged across Europe reaching its icy fingers as far South as Italy and the Languedoc (which don’t usually see frost) through Bordeaux and Burgundy (which are prepared for frost, but have been overwhelmed by the worst frosts in decades). The French Government has declared a disaster and has set aside a fund to compensate for the billion of euros of damage.
This side of the channel, there is no disaster fund. Just desperate vignerons trying to protect their vines. What can they do?
Precious little – if you get the wrong type of frost.
If you get an advective frost – that is, where a mass of cold air blows in from somewhere else, usually Scandinavia, – then there is very little that can be done. You can only protect your vines against this if you spray them with water throughout the night from an overhead shower system that you have already installed in the vineyard. The energy released from the water freezing is enough to protect the buds and young leaves.
Your chances are better though if you get a radiative frost. During the day the sun warms the ground, and at night, the ground radiates the warmth back towards the sky. If there is no cloud to trap it, the heat escapes. The ground get cold, then the air near the ground gets cold, and if it is not blown away by a wind, it gets colder and colder and freezes. Sounds bad, doesn’t it? Bizarrely, if you have to have a frost, this is the frost you want. At least you’re not powerless. You can fight it. You can warm up the vineyard by a couple of degrees through grit and hard work. You can burn candles, or burn ‘smudge pots’ (little heaters) set out among the vines. OK, both options are inefficient and pollute the atmosphere, but they could just do the trick. Alternatively, you can use huge fans that will displace cold air with warm air (assuming you have some warm air around). Helicopters can do this too, but – unlike in Australian vineyards -we’re not allowed to use them for this in the UK. If you don’t have warm air, you can make some – buy heaters attached to huge fans which you can wheel about the vineyard in the early hours. Of course, this won’t protect the vines if it is very cold, but if you only need a couple of degrees it could make the difference.
Here at Ambriel HQ we have been lucky. So far.
We’re on a hill so the radiative frosts tend to roll off, and our greensand rock retains heat for a bit longer at night keeping the vineyard a little warmer. So far, so good. We have not been burning or blowing in the vineyard at nights, but our hearts go out to those that have.
But its not over yet. Our crop could still come a cropper. While it may be May, its still cold. It could turn nasty. In Europe the ‘Ice Saints’, a quartet of saints including – amusingly – St Pancras, (whom I always associate with the railway station that takes you to the frozen North) trick people by arranging a frost on their respective feast days in mid-May. Its devastating for seedlings. My grandmother always cautioned ‘Ne’er cast a clout ‘till May be out’ – which was odd, because she didn’t usually speak with an accent. Or cast clouts.
Luckily, vines are very clever. They have evolved for 66 million years, so instead of producing one single bud, they have three. So if the first gets frosted, they have back up.
‘So why all the fuss’ I hear you ask. Why don’t those vignerons just stay tucked up in their nice warm beds and wait for the back up buds? Its all about the crop. The second (or third) buds start growing so much later on in the season that they don’t have time to ripen grapes before the winter cold hits. The crop is lost. The vine doesn’t mind – its quite happy just being a hedge for a year, and there’s always next year for that grape-growing activity. It does leave the winemaker emptyhanded and idle though.
Never fear. When it comes to April, I’m more Chaucer than TS Eliot. The Canterbury Tales admires April’s fecundity:
‘What that April with his showres soote
The droughte of March hath perced to the roote
And bathed ever viene in swich licour,
Of which vertu engendered is the flowr;’
So April brings new life, new hope, new grapes, new wines. There’s light at the end of the tunnel. Its May: ’Now is the month of Maying/ when merrie lads are playing. Fa la la la la, la la la la.’
(but I’m still crossing my fingers)