There are several methods of harvesting your gourd crops. In warmer climates, the gourds can be left on the vines to dry all winter. But if you live in a colder climate, there is great risk of frost damaging any immature gourd that hasn't "hardened off" (reached full maturity).

I live in a climate of hard frosts, below zero temperatures and snow during the winter months. So in the fall I begin to keep a close eye on my gourd vines and gourds. I don't have the luxury of just ignoring them and allowing them to sit in my garden.

The vines will begin to die off and turn brown. This is a good indication that your gourds will be ready to harvest before too long. As the vines die, they stop sending nutrients to the gourds. The gourds have most likely reached their maximum size at this point and won't get any bigger. You should reduce the amount of watering or stop watering your gourds at this time. Less watering will help speed up the vine dying process needed to be able to harvest your gourds. Just make sure your vines have started dying off on their own before you reduce your watering. Let the vines completely die before harvesting your gourds if you can. If the vines are still green, they are still providing nourishment to the gourds. You want to leave your gourds on the vines as long as possible, but it is best to harvest them before the first HARD FROST.
I have covered my bottle gourds if an early frost is predicted. Usually, these early frosts are light and the temperature still warms up during the day. These light frosts will hasten the vines to die.

Don't harvest the larger type gourds too early. Wait until the gourd stems are brown and show no sign of life (green). Immature gourds, gourds that have started to grow late in the season, will start to shrivel up on the vine. This is another good sign that your larger gourds are almost ready to harvest. This final stage before harvesting is when the shells of the gourds are thickening, called "hardening off".

When the stems of the gourds have withered and turned brown, cut off your gourds as close to the vine as possible, leaving at least 2 to 3 inches of stem connected to your gourd. NEVER TWIST OFF THE GOURD. Use a sharp knife or trimming shears to cut the stem from the vine.

When you harvest small ornamental gourds, you want to pick them early while their colors are still vibrant. These smaller ornamental gourds are usually not used for Gourd Art carving and crafting, but for their aesthetic value in displays.

There are several methods for gourd harvesting. What I have explained works best for me and the climate I live in. You may find a way that better suits your gardening method and the type of gourd you grow.

When harvesting your gourd crop......HANDLE WITH CARE! This pertains to any "green skinned" gourds you harvest. They bruise very easily, and bruising can cause them to rot when drying. Don't bump them together or scrap the skin. This leaves a weak spot on your gourd that will rot. If your gourds have turned brown on the vine before harvesting, then they have already begun the drying process and will not bruise.