Bloom and Fruitset

On June 12th, I wrote a blog called Stages of Flowering and predicted that flowering would be on July 6th. Well, while we were nipping and tucking our Cabernet Sauvignon, my husband looked over to the Chardonnay and saw that some of our plants were flowering! That was way back on June 19th!
Why is knowing the date of flowering important? With the data that we have been tracking, we believe that between flowering and harvest, in our vineyard, it is approximately 90 days. If flowering came on July 6th, that puts harvest around October 4th.
We have come to learn that our Chardonnay is always the first to bloom (also called anthesis), but we were surprised to see that our Cabernet Franc was also in bloom! On June 21st, here is where our vineyard stood with respect to percentage flowering:

Variety	% Bloom on June 21
Chardonnay	50%
Cabernet Franc	40%
Auxerrois	40%
Chenin Blanc	10%
Cabernet Sauvignon	Not in bloom yet

It is very interesting to have visitors in the vineyard during bloom because many believe that the pre-bloom flowers are already the young grapes.

Superficially, the two stages do look remarkably alike, but on closer inspection, there is a discernible difference. The pre-bloom grape buds have ridges that are formed by the presence of the calyptra or flower cap which are actually the petals of the grape flower.
Since flowering is a full 2 weeks earlier than what I thought, our harvest should be more like the end of September, Mother Nature willing!