Fruit Set Begins

June 17, 2013 § Leave a comment

June 17th, 2013

Flowering began about 15 days ago, and we are beginning to see signs of fruit set.  Fruit set describes the period after flowering when a fertilized flower begins to develop a seed, and, more importantly for us, a grape to protect the seed.  We had a few storms and strong winds during the flowering stage, but we also had some sunny, breezy days, which are ideal for successful flowering, so we’re seeing a few issues within flowering – clusters with less than ideal “set” grapes – but overall things are looking great.

fruit set

Successful fruit set in Chardonnay – those are tiny, tiny grapes, and will expand over the next two months.

This period is crucial for cluster size and overall yield.  Not every flower fertilizes – actually, averages seem to be around 30% in most vineyards, although this number can vary considerably.  Cluster size and cluster density are determined by the percentage of fertilized flowers, as well as variety and clone.

 

Hens and Chickens

June 10, 2013 § Leave a comment

June 10th, 2013

We’re sitting now at full bloom for most varietals in our vineyards, a bit late in the grand scheme of Virginia but not as late as our budbreak and early growing season, as we’ve seen the season speed up since its late inception.  The vines have worked their way through the Spring floral stages, and the flowers for each cluster are spitting their caps off (a process called anthesis, which occurs in all plants and is basically the period during which the flower is fully functional) in order to expose the flowers to allow for pollination and fertilization.

Grape flowers before anthesis (left, with cross section center left), during (center right), and immediately after (right)

Grape flowers before anthesis (left, with cross section center left), during (center right), and immediately after (right).  Yes, this is a picture of a book.

The weather will determine the success of flowering and, thus, fruit set.  Excessive heat, sunlight, wind, and rain can all impact fertilization.  Additionally, water stress, nutrient stress, inefficient leaf area, or imbalances within vine growth can result in poor fruit set or loose clusters.  Certain varieties are more picky with flowering than others.  Viognier requires very balanced, calm weather patterns.  Without good sunlight and still winds, Viognier fruit set can be frustrating, with numerous “shattered” berries leaving holes and gaps in the clusters.  On the other hand, Chardonnay is pretty easy to please and seems like it would have great set in a hurricane.

Cabernet Franc clusters at about 30% bloom.

Cabernet Franc clusters at about 30% bloom.

There are some great terms describing poor fruit set – “coulure” (from the French couler – to leak) describes excessive abortion of flowers and ovaries through shatter; “millerandage” or “hens and chickens” describes inadequate seed development in a portion of berries (“hens” are large, normal berries, while “chickens” are small berries with tiny seeds); and “shot berries” are small, green, hard berries that essentially never mature past the ovary stage.  Each of these issues leads to difficulties with yields as well as final wine quality.  On a standard year we will see a bit of all three, depending on the weather and vine strength, but it’s too early to say much about 2013.

The vine growth previous to bloom and flowering has been quite good.  While we did have some frost damage around Mother’s Day, it has been made up for in strong, even growth at all three vineyard sites.  In fact, this is the most evenly distributed growth I’ve yet seen from our vineyards, which is very promising for final wine quality, especially for varietals like Cabernet Franc, Cabernet Sauvignon, and Viognier, which often struggle from uneven ripening, causing some difficulties in winemaking.

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