Further explanation: Bare lines of vines, a coo of a pigeon in the distance, and the crackling of footsteps as a vineyard manager passes through the rows in the morning light. He has done this many mornings, but his steps stop as he notices something different. There it is…light green, soft, even a little fuzzy…it is a bud.
Each year we eagerly wait for bud break to occur. This is when the vines push open leaves much like other plants during the spring. Dormant vines awake when daylight and temperatures increase, which encourages the vines to pull up stored water and macro-nutrients (nitrogen, phosphorus, potassium) from the roots to the limbs. This up-flow of water and nutrients push open the buds. You would think that after leaves push open that it would mean photosynthesis would occur immediately, but it does not. It takes the vine a little bit of time, leaves the size of about silver dollars, before that process begins.
One of the most important parts of bud break is that it is a measurable starting point for the vineyard. We can actually start the clock for when pivotal moments will occur. For instance, we now know we are about 150 to 200 days away from harvest depending on the grape variety. It seems like this then would mean that bud break itself is actually a markable date, but it’s not that simple. This is still farming, which means everything is variable. When bud break occurs depends on a few things. Each terroir is different. And you can probably guess, each variety of is different.
A cooler terroir means that bud break will be later, while a warm terroir like in Paso Robles, CA will have an earlier bud break. In Paso Robles, we have seen buds as early as February. Although for us this year (2018) we are running a little slower as we have had a cooler spring. Each year is different! Another factor is micro-terroir. The difference between locations of vines in a single vineyard will even come into play. A hillside vine will have bud break because of its elevation, but a lower valley vine will still be dormant. Lastly, varieties will have bud break at different times. In our Adelaida Vineyard, our Malbec and Cabernet Franc had bud break first, but the Cabernet Sauvignon hit the snooze button. As you can see, there are many variables that go into this and this is just one part of the vine cycle!
While there are variances in the cycle, one consistent thing is temperature. Vines are very dependent and particular about temperature. Vines prefer gradual temperature increases for bud break, but they don’t always get that. Sometimes they get awoken from slumber with a warming trend and then hit with a freeze. That is why vineyards have tall fans to help with frost protection. A freeze will damage the cellular tissue in the leaves and the leaves will then turn black. It’s awful. This then kills the growth for your year and can sometimes decimate a vineyard. Bud break is basically the infancy stage of the vine. You want to protect it because the leaves are soft and fragile at this stage, much like you would with a newborn (and well, we all know parenting doesn’t stop there). So, that is the one thing all farmers can count on is frost season and the need to be vigilant.
After bud break, we now watch as the leaves begin to grow (obviously). Photosynthesis will begin at a certain point and once that happens the shoots of the vines will really take off as the vines will receive something that they love, much like humans, carbs! Up next is flowering, so stay tuned.