This is a great kids craft idea to introduce young kids to clay and ceramics. It looks at form, function and texture and can be accompanied by a nature walk a treasure hunt to source materials. I did this when I was 4 and enjoyed it so much that to this day I remember the whole experience.
Get some light coloured air drying clay. Roll it out on a plastic covered board. Use shells, lego blocks, bottle caps, branches to press into the clay to create interesting textures.
Trimmed the edges with a plastic knife and rolled into a cylinder pressing overlapping clay gently together. (If you want more secure joinery, cross hatch where clay will overlap, with a toothpick or scure and lightly paint with water before joining two surfaces together). Attach a circle of clay for the base, neaten edges with a knife once attached. Cover loosely with plastic and leave to dry for 48 hours outside. When the clay is completely dry you can paint, but be sure not to use too much water or paint or the clay will soften. We used sparkly nail polish as well for a nice bling finish! Make sure to glaze it if you want to use it with water.