Answer: Grapes have a certain heat unit requirement (number of days over 45F) and the requirement varies according to grape variety. You can't force a grape to ripen; it is all weather dependent. Therefore, if you choose the right variety for the growing conditions in your garden, you'll stand a better chance of having ripe grapes before fall sets in. You'll need to plant the grapevines in your yard so they can develop an extensive root system and be better able to regrow if the winter weather is extremely harsh. If you choose the hardiest, shortest heat unit requiring variety, you'll have less winter damage and a better chance for a large grape harvest. Here are a few suggestions:
Good luck with your grapevines!
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