Deep Sleep-The untold story
Winter has arrived in the Sierra Nevada range. The snow is falling and wildlife tracks of every kind can be seen all around the ranch. The land is still and quiet, peaceful and serene. I can hear the slightest movements around me as the snow covering the ground has absorbed the sound waves in the air.
The grapevines have lost all leaves and appear barren, even lifeless. It’s a time for rest and renewal. This important time of year for the health and wellbeing of the vines is called the period of “dormancy”. The grapevines are hibernating!
It may seem that little is happening in the vineyard, but the grapevines are still very much alive and enter this stage in their annual lifecycle, slowing down their normal function, to protect themselves from upcoming harsh winter conditions. Dormancy is just as critical in the health of the vines as spring budding. Before laying low or hibernating for the winter, the vines depend on a nice drink of water to keep up their strength through the winter months. The vines are surviving on carbohydrate reserves stored during the previous growing season. They have to survive on their stored reserves from leaf fall until new shoot growth in the spring.
Dormancy is triggered by shorter days, lessening the photoperiod signal in plants, along with cooler temperatures. At leaf fall, new buds are already prepared for low temperatures. Acclimation occurs well before the onset of freezing cold temperatures. The vines begin by decreasing the level of water in various tissues with the process of dehydration through movement of water to intracellular spaces and accumulation of carbohydrates and protein complexes that bind water and serve as cryoprotectants so the plant cells won’t form damaging ice crystals and “freeze” in cold temperatures.
A specific amount of “cold” in the grapevine needs to happen in order for bud break in spring. If not, delayed bud break or prolonged dormancy can later effect spring flowering and growth of the vines, having a negative effect on quality and quantity of the new crop.
During winter, I feel like laying low and becoming “dormant” myself, sitting by the fire with a glass of wine, resting, enjoying the memories of harvest past! When I began growing grapevines 23 years ago, I thought I’d get to do just that! Rest all winter, enjoy some deep sleep and hibernate like a bear. Instead, as I learned, winter was time for me to prepare for spring! Time to perform maintenance on farm equipment, sharpen my pruning tools, mend fences, tune small engines, purchase new equipment, new gloves and boots, then schedule vineyard activities before spring pounced upon me!
In the winery, I learned, winter became the time to order bottling supplies and bottle wine, rack wines to preserve their freshness, service the winery equipment (forklift, press, de-stemmer, power washer, pumps, and bottling equipment). Winter in the winery is also the time to sell wine, ship wine and host wine events!
Deep sleep never came! Laying low? Rested, revived and refreshed? I think you get the idea that farmers never really rest or go “dormant”, but somehow, probably due to consumption of our crops, farmers come out of winter into spring still budding!
Here’s to a restful New Year!