If they are regular North American cantaloupes, They will slip (release from the vine) when ripe.

Don't know what kind they are. The seeds were from some cantaloupe I got at the Farmers Market last year.

They're about the size of a softball right now. Will they continue to ripen until frost? If they aren't ripe at frost, will it help if I cover them when it frosts?

Deanna

They will get slower and slower as the daylenght decreases. The longer you can keep the vines alive, the better your chances of getting a ripe cantaloupe. Once the vine dies they are through.