Vineyard Talk: Spring 2021 Update

Herzog Organic Vineyard
Spring - hard work to achieve our pure, complex and concentrated wines naturally.

The consequence of our commitment to produce the healthiest and naturally concentrated grapes in our stony vineyard organically, is extreme labour intense work (at high cost). Spring being the busiest time in our meticulously finely tuned plot of land! Everything after bud burst happens in short sequence and frequent rainfalls demand that we work every waking hour when the weather is favourable to get on top of all these important tasks. Shoot thinning, sowing, wire lifting (3 times for 3 layers), spraying (about every 10 days), under vine weeding (twice), cultivating, mowing (many times especially with the current good rainfalls), top-grafting, leaf-plucking and lateral removing, all happen within a short period of time.

It feels like we were just dropping the wires after long weeks of hand-pruning to put them up again. Despite a slower start with more rainfall and cooler temperatures compared to last season, growth picked up quickly with temperatures gradually increasing. More frequent rainfall together with beautiful sunny days accelerated growing and bud burst happened around the end of September the same time as last year.

Whilst I write this, the faintest floral whiff of a breeze tempts for a walk through the vines. The enthralling scent of flowering vines is both invigorating and uplifting but there is so much to do… read on for all the detailed work involved!

Soon after bud burst, when shoots reached around 20 cm long, we started with extensive shoot thinning for a reduced and healthy crop. We clean up the head of the vine and take off the shoots at the end of the cane where there is most growth, inclusive all double shoots and the ones carrying no fruit. A particularly time-consuming process which requires concentration and diligence.

Disease Control - at the same time the vines need protection from powdery mildew, a widespread fungal disease. Organic vintners are required to manage powdery mildew without the wide range of synthetic fungicides commonly used in viticulture today. Instead, alternative disease management strategies that incorporate cultural control techniques and a limited range of treatments like organic mineral oils and sulphur is applied. That’s why meticulous shoot thinning is so important. With fewer shoots there is good aeration, and the spray can reach the inner leaves of the canopy with less spraying needed. To monitor the weather is important too. It makes no sense to spray only for it to be washed away by a downpour, vineyards know no weekends...  

To promote Biodiversity (as opposed to monoculture) we planted many diverse grape varieties and clones but also fruit- and other trees on headlands and borders. We created a flowering meadow in the middle of the vineyard to allow a natural corridor from the associated Biodiversity of the neighbouring rivers flood reserve land inclusive all flora and fauna that colonize this agro-ecosystem.

Every spring we also sow a few rows shared throughout the vineyard with beautiful wildflowers. The more diverse a vineyards ecosystem is, the more resilient or self-regulating it will be. Biodiversity allows balanced pest control away from chemicals to the control provided by natural enemies (e.g. to attract beneficial insects that thrive on harmful invertebrates).

Changing grape varieties... The weather beginning of November was ideal to graft new varieties on our deep rooting 25-year-old vines. As they age, vines learn to self-regulate. Yields come into balance, and grapes ripen more evenly. Older vines also produce smaller berries, which lead to more structured wines; there's a greater ratio of tannin-packed skin to juice. Precisely what is required for our Cabernet Sauvignon, Cabernet Franc (Spirit of Marlborough) and Montepulciano. We like to stick to our long maturing philosophy, keeping these iconic wines back for you to enjoy at perfect drinking age. But with higher demand they roll over too quickly for us. Hence, we had to sacrifice some Pinot Gris and Riesling. We also keep in mind that with harvest arriving each year earlier it maybe wiser to concentrate on our late ripening varieties.

Growing so quickly means we need time to put the first wire up to support the growth and protect the shoots from breaking as the strong nor westerly hits them.

The frequent rainfalls not only accelerate the growth of the vines but also the weeds, which unfortunately grow as enthusiastically up to the height of the vines, competing for moisture and matter in the soil with the potential to trigger diseases. This means repeat under-vine weeding and mowing, mowing, mowing…

The excellent draining of our stony, gravelly terroir means much dryer and warmer soils, which is great for our late ripening varieties, but have little water holding capacity. That’s why Hans must cultivate every second row before the dry season starts. Any cover crop will compete against the vines for moisture in our semi-arid climate. This also works to aerate the soil, making it easier for air, water, and nutrients to get to the roots of the plants. Another advantage is that a bare, firm, moist vineyard floor absorbs heat during the day and releases it during the cool Marlborough summer nights, increasing the air temperature by as much as 1.6 to 2.2°C.

Too much cover crops bring nitrogen into the soil which stimulates growth and would interfere with our low yield philosophy. After vintage we let the cover crop start to grow again.

But its already time to lift the second wire as the vines achieve about 40 cm in length. In no time the growth will reach one metre and we will need to lift the final, third wire.

Canopy Management - soon we will start leave plucking and lateral removing, pulling off the leaves that are growing in and around clusters. Light and air around the clusters promote healthy grapes and discourage mildews, rots, and pests from attacking the clusters. Protective sprays but also leaf fertilizer like liquid seaweed will get into the canopy. We remove leaves first on the side of the vine that gets morning sun (east) and only a month later a bit less leaves of the more intense afternoon / evening sun side (west). While sun is needed to ripen the fruit, too much direct sunlight beaming down on the fruit during low humidity can cause the fruit to burn.

Hopefully we get all done until Christmas to enjoy a few relaxing days together…

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