Vinegrowing Course - Day 5

Today's topics for the morning theory session were "vineyard floor management" (a subject which might historically have just been called "weed killing" but nowadays is portrayed in a more positive light) followed by an overview of approaches to sustainable viticulture.

As I remember my Mother (an avid gardener) saying once, there is no scientific definition of what a weed is. It's simply any plant growing somewhere you don't want it to be. Opinions on the presence of other plants in the vineyard (apart from the actual vines) seem to have varied historically, and part of the reason the subject now tends to be referred to as the slightly more constructive "vineyard floor management" is the acceptance that there can be advantages to having other species of plant around the vines. There are certainly disadvantages to weeds - chiefly that they compete with the vines for resources, and they make access more difficult. They can also harbour pests, and less surprisingly can increase the frost risk.

On the positive side though, among other benefits "weeds" can help to prevent soil erosion (recently the subject of a report concerning Prosecco), they encourage biodiversity, can look appealing and the competition for resources with the vines can be a good thing as this can reduce vigour and encourage higher grape yields. 

The traditional method for controlling weeds is cultivation (i.e. churning the soil up - for example with a disc harrow), however this tends to be a lot of work, and only briefly suppresses weed growth. Other approaches include temporary cover crops, mulching, flamethrowers (!) and using animals to graze on the weeds (sheep are apparently very common in English vineyards) - but, apparently, none of these are as effective as herbicides. Although we were told viticulture is approaching a challenging juncture in this regard, given that increasingly more and more of these chemical weedkillers are being banned and the industry will need to rely more on the alternatives in the future. 

This led the way into an overview on sustainable viticulture - organic, biodynamic and other approaches. I hadn't fully realised quite how much snake oil there was in biodynamic viticulture - which goes somewhat further than the organic approach - working to phases of the moon, and odd practices involving burying cows horns all sound a bit pagan to me, and not very scientific.

In the afternoon we headed over to the vineyard, and for the first time we actually had pleasant weather! It was very nice to see Rock Lodge and Deer Field in blue sky for a change.

Tom started by recapping some of subjects covered during the morning's theory session, and showing us some relevant bits of machinery which can be attached to a tractor for cultivation. We then headed out into the vines to demonstrate attaching a new wire to the trellis.

He also showed us some examples of Pendelbogen training system, which takes a double Guyot pruned vine then arches the resulting two canes to create a letter 'm' shape, or in some cases a full heart shape, with the tips of the canes bent all the way back to touch the trunk. This apparently promotes better sap distribution and therefore more even shoot growth and higher yields.

We practised dropping the canopy wires down ready for tying up, and finished off back at the shed for a demonstration of the grafting machine. This is essentially something a bit like a hole puncher you'd use with paper, the idea being it makes a socket in the scion and a plug in the rootstock, so that they fit neatly together.