Annual Growth Cycle
The Annual Growth Cycle of grapes starts in winter with Dormancy were Pruning occurs. Spring signals Bud Break and Shoot Development. Flowering & Fruit Set, Berry Formation and Verasion all occur in the summer. And the Autumn brings Berry Ripening and finally the rewarding Harvest.
Dormancy
Pruning
Pruning Start:
2018 Feb 20
2019 Feb 19
2020 Feb 21
2021 Feb 1
Pruning Complete 2018 March 21
2019 March 26
2020 March ?
2021 March 26
Grapes are dormant all winter long and can be pruned anytime then. Traditionally we've started pruning in February after President's weekend after snowbirding. But in 2021 we stayed home with COVID and started earlier. Transplants and grafts are also done at this time.
We use the cane pruning technique. It is complete when all old canes have been removed except for two canes in the middle which are laid over to start the new canes to grow up from last year's buds. Pruning is the first step of canopy management
Bud Break!
Shoot Development
Bud Break Dates:
2018 April mid?
2019 April 16
2020 April ?
2021 April 20
Shoot Development:
May & June
Bud Break marks the beginning of the Grape Growing Season. Note deer fence in back ground is up because new young shoots are their favorite yummy treat.
Leaves and shoots expand and cluster florets develop. Also note that the war against the jungle of weeds begins as all plants start to grow rapidly. Shoot Thinning is done with five shoots 3-4" apart on each side of the plant.
Flowering & Fruit Set
Berry Formation
Fruit Set Dates:
2020 June 24:
2021 June ?
Berry Formation:
July & August
Grape flowers typically bloom for eight to ten days when they are first pollinated and two to three days later fertilized. The fruit set stage follows almost immediately, when the fertilized flower begins to develop a seed and grape berry to protect the seed.
The grape berries are green and hard to the touch and enlarge rapidly. The weed jungle also continues to grow requiring constant battle. Shoot Training also occurs at this time as shoots are positioned between the two lower training wires and then the two upper training wires as they continue to grow higher.
Veraison
Berry Ripening
Veraison Dates:
2019 Sept 3
2020 Sept ?
2021
Ripening Month:
September
Veraison is when the grape berries reach full size, start to produce sugar and change color. It also signals the beginning of when birds take an interest and the bird net needs to go up. Also lateral stems and hedging occur to control the leave count on the plant.
During the ripening phase the grape berries continue to accumulate sugars, while acidity decreases. Berries are becoming softer and they are rapidly increasing in size. Note bird net in the background above the grapes.
Harvest
Harvest Start Dates:
2018 Sept 25
2019 Oct 4
2020 Oct 2
2021
Sugar content, color, bunch and berry size and uniformity are all measured before harvest begins making when to harvest the most difficult decision a vintner makes all year.