Here's how to grow gourds in a mold to create any shape you want.
Even portrait sculptures. It's an ancient technique from China.
This method also works for other vegetables. Portrait pickles anyone?

Jim Widess, proprietor of "The Caning Shop" in Berkeley CA and author of many books on gourd craft walks me through the steps.
These molds and gourds were made by the Chinese master Zhang Cairi.

Step 1: Get or Carve the Original Pattern

Here's Jim Widess holding mold-grown portrait gourd sculptures of himself.
The light-colored one is the gourd's natural color. The darker one was stained with dark tea.

Almost any object can be used as a pattern for gourd mold.
Most likely you'll want to cast your head full-sized and make a mold from that.
Watch this space for an instructable detailing that process.

The mold must be slightly smaller than the gourd's natural size.
Match the gourd to the rough size and shape of the object you're molding.
There are gourds that grow very large and in a variety of shapes.

Step 2: Head Patterns, Mold, Gourd

The original clay sculpture is on the left. Then Zhang made a latex rubber mold over the original, pulled it off, and cast hard rubbery plastic resin in that. That's the white version standing to the right of the original.

That white pattern was used to cast the mold you see here.
This particular mold has a rubber interior and plaster around that to support it.

From left to right are the original carved pattern, plastic resin duplicate, and an actual gourd grown in the mold.

Step 3: Gourd in Mold

Depending on your climate, the gourd seeds are planted in the spring in a sunny place that gets plenty of water. If it's cold you can sprout and start them indoors. It's best if you have a trellis for the gourd vine to climb up. When the baby gourd is just big enough, put it in the mold.

Step 4: Clamp the Mold Shut

While I am taking this picture Jim is explaining that next you
clamp the mold shut by tying it with string or wire.

Step 5: How to Hang the Mold

While I am taking this picture Jim is explaining that you next suspend the mold with string or wire so the vine doesn't have to bear the weight of the mold.

Step 6: Nature Takes Its Course

If you harvest a gourd when it has reached the size you want, it will be soft and won't keep well.
You must wait until the season has finished and the vine starts to die. When there are six inches of brown dry stem above the gourd, you can harvest it.

This picture shows approximately how the gourd sculpture looked in the mold. It was a much lighter color at actual time of harvest.

Step 7: Remove, Dry, and Finish the Gourd

This mold has a flexible rubber lining which makes it easy to remove from the gourd.
A plaster mold adheres to the gourd more tenaciously and usually the mold is destroyed in the course of removing it from around the gourd.

The gourd is then allowed to dry slowly, and the outer coating called the "cuticle" is removed.
Then the finishing steps, if any, are done.
On this gourd, the details of the face and hair were then traced with the point of a jade knife to enhance the detail, It was dyed with dark tea, and a coat of varnish was applied to make it shiny.

Step 8: The Finished Gourd Sculpture

Here's Jim again with the finished sculptures.
One is tea-colored and one is the natural color of the gourd.
He's standing in front of a gourd vine [www.caningshop.com at his shop].

For more details on Zhang Cairi's methods, get a copy of the book.

This method will work for many other vegetables also. Portrait pickles anyone?