Between the Vines is a biweekly column on wine and wine making in the Livermore Valley region. This column information was contributed by Brent Amos, a winemaker at Las Positas Vineyards.

What's happening in Livermore Valley vineyards this month?

The vineyards are pretty quiet at this time of year because grape vines are deciduous plants. In late autumn, triggered by short days, the vines drop their leaves and go dormant for the winter.

Right before dormancy, we want the vines to take up nutrients to create a reserve that they can access during "bud break" in the spring when increasing temperatures and longer days stimulate the dormant buds to swell and open. We applied an organic fertilizer early in December to allow the vines to store nutrients for these young leaves when they need it next season.

We are also seeding cover crops where needed in our vineyard to improve soil health. In areas to be planted with new vines, we grow a mix of wildflowers and mustard. In our established vineyards, we have perennials and grasses that return every year. After the flowers have bloomed in the spring, we till the cover crop into the soil to replace organic matter and keep the soil healthy. Cover crops also attract beneficial insects such as spiders and ladybugs that help to control pests.

It's been a dry season so far, so we are applying small, occasional amounts of irrigation to mimic rain. This keeps the soil healthy and receptive to water. If allowed to completely dry out, the soil will harden too much and the water will not be able to follow the usual pathways to reach the vine roots.

Las Positas Vineyards has two different estate vineyard sites in Livermore. Most of our fruit comes from our Kalthoff Common vineyard, which is located in the northwest corner of Livermore. It is one of the coolest areas in Livermore Valley wine country, allowing the fruit to ripen more slowly. On this site, we grow four different clones (types) of cabernet sauvignon, malbec, petit verdot, barbera, petite sirah, and two different clones of tempranillo. These vines are five years old.

Our second estate vineyard is on Wetmore Road beside our winery. The vines here are seven years old, and we have syrah, petite sirah, cabernet sauvignon (giving us a total of five different clones), nebbiolo and chardonnay.

To taste wines made from the fruit grown by Las Positas Vineyards, please visit our winery at 1828 Wetmore Road in Livermore or find us online at www.laspositasvineyards.com Livermore Valley Wine Country Events:

wine country events

  • Acoustic Guitar at Las Positas -- 2 to 5 p.m. Saturday at Las Positas Vineyards, 1828 Wetmore Road in Livermore; www.laspositasvineyards.com. Cost: $5. Come join us in our tasting room for a special holiday tasting and enjoy live music played by local acoustic guitarist Jimmy Ashley.