Episode 0004:
Finger Lakes Viticulture – April 29, 2021
The growing season is barely underway, and the white knuckles and sleepless nights have already begun, particularly in light of our cold event and snow last week. I promised you that in our “In the Vineyard” series, which airs biweekly between our long form interviews, you would have the chance to peer into the thoughts and experiences of Finger Lakes wine growers, as we experience 2021.
April began with daily temperatures in the forties and fifties, and nightly temperatures ranging from the twenties to the thirties. After the first week of April was behind us, temperatures grew unseasonably warm as we experienced our first days in the 60’s and 70’s in many, many months. I think it was probably October or early November, since we had temperatures this warm. For nearly a solid week, daily temperature highs were in the sixties or above, which is important for a concept called growing degree days.
In the Finger Lakes, we generally consider April 1st through October 31st to be the growing season. That growing season is dependent on temperature, specifically air and soil temperatures. Grapevines will begin to signal that dormancy should end and the growing season should begin when soil temperatures remain around 50 degrees. For soil temperature to be at that point, the ambient temperature must be greater than that, or at least above fifty for an extended period of time.
As part of monitoring temperatures, we use a calculation and temperature tracking system we called Growing Degree Days or “GDD.” Essentially, to calculate GDD you take the maximum temperature and the minimum temperature in a day, and calculate the average. You then subtract 50 from that number, which is our baseline temperature for grapevine development. The difference will give you the GDD number for that day. If the result is a negative number, you simply calculate that day as 0. For example, if the high on a given day is 70, and the low is 50, you add them together and divide by 2 to find your average temperature, which would be 60. By subtracting 50 from 60, you end up with a measure of 10 GDD for that given day. By conducting this exercise daily, and keeping track, you can compare it to previous vintages to see how far ahead, or behind, you are in a given season. Although you can calculate GDD with the start of the year, the numbers actually start to matter around April first, since that is generally, the period when we start to accumulate growing degree days.
Generally, they don’t accumulate so quickly. As you can see in this chart, the number of growing degree days we began accumulating in April was pretty high. And then, we fell off a cliff.
We experienced an event last week that every wine grower fears, and that many in France endured this year as well - the late frost. We didn’t just have a frost though, we had cold temperatures and snow.
The unique thing about the Finger Lakes, is just how much the lakes regulate the mesoclimate, or the weather and temperatures, in any given location. Proximity to the lake, aspect, and a number of other factors determine what the impact is. As a general rule, there are vineyards in the Finger Lakes that are warmer. During the growing season, this means you can accumulate more ripeness. On the outer bands of the growing season, that is budbreak and harvest, frost can cause damage to the vine. In particular, low temperatures this time of year can damage buds that are starting to grow this year’s fruit. If you’ve experienced bud break, in other words, the bud has begun opening and the vigor of the vine has begun to push its first vegetation, the cold temperature can freeze the tissue and even young grape clusters, and severely impact fruit production. The key temperature we look for that will cause damage to grape bud or vegetative tissue, is 28 degrees.
That kind of event occurred this week, with temperatures dipping, snow falling, and chilly winds blowing. Ironically, the snow and wind were welcome. Snow, and even ice, can buffer a grape bud and regulate the temperature, keeping it very cold, but at the freezing temperature of water, 32 degrees. Likewise, air flow can help keep the temperature slightly higher as grapevines don’t generally feel wind chill the way we do. Cold, still air, is the most dangerous situation.
Quite frankly, we don’t know what the impact will be quite yet. In our vineyard we were witnessing some of the buds starting to swell. For vinifera grape vines, we are still a few days and weeks away from budbreak. In speaking with other growers, everyone is in a “wait and see” mode, with most holding out hope that we grazed a bullet. We will certainly keep you updated on how this event impacted the region.
Say your prayers, and send good thoughts. This was a very difficult start to the growing season. I’ve been through enough of these cycles in the Finger Lakes to still remain extremely optimistic for 2021.
I remember a conversation I had with one of our growers, Jeff Morris, back in 2012. It was a warm, dry year, and I remember asking him how much we were ahead of quote “normal” in vine development. His response was, there is an average in the Finger Lakes, but there is no normal. No year is normal.
2021 is out to prove this statement right. So far, there are challenges, and still a lot to find out. Was it normal to get this cold and this much snow in late April? Well, it certainly wasn’t the average.
As dandelions are beginning to sprinkle the grass with dots of yellow, and trees begin to don their fist brushes of green, spring is arriving in the Finger Lakes. There is an inevitability to it in the air, and despite a few days on the horizon that may be some cause for concern, the race to harvest is nearly underway.
If you have any questions about growing grapes in the Finger Lakes, or those things that we are wrestling with this time of year, be sure to drop a question in the comment sections of YouTube of Apple Podcasts. We’ll answer your show on the air, and share any insight we can.
S1 EP0004 - In The Vineyard