The gourd growing season will soon be over. Gourd growers in the colder areas of the country always worry if their gourds have matured enough. It is important to let them on the vine as long as possible.
You may have heard you need to remove the gourds before they are hit with a frost. I think this misconception has come about because of the small ornamental gourds with their colorful skins that are used for fall decorations. Sure, their skins could be damaged with a frost, but we have no such concerns with the hardshell gourds grown for crafting purposes.
We are more worried about maturity and thick shells. Even when the leaves are blackened with frost the vines still can supply the gourds some nourishment. So leave those gourds in the fields as long as possible.