I have a three year old cabernet grape vine in a very large frost free pot and the grapes are so small and beginning to ripen.Do they grow bigger with age?
How often and how much do you fertilize? I am still new at grapes but I have heard that you need to fertilize with a good dose to get a descent crop. And if its for your first crop then yes it will get bigger on the next crop.
A 3 year old grape is not old enough to bear decent fruit. We pinch clusters until the 4th year. The vine needs time to establish it's root system to support the fruit. Also, container vines will usually not grow as hardy and prolific as those in the ground.
Our in-ground grapevines are huge, but those in containers just don't have the same vigor! We put them in containers because we wanted to get a head start on a move, and now those in containers will be planted in ground. Many are 3 years old, but the transplant will set them back, so no grapes for us next year for sure. Those in ground will be dug up and transplanted, and it's back to a two year old vine for those 5 year old monsters.
All our vines are on drip systems. They do like water!