I want to put up a "long wire" with the feedpoint at one of the back end
corners of the garden. I need a good RF ground.

If I got a length of 6 foot wide copper sheet and made out of it a cylinder,
say 6 feet in diameter, and then placed that cylinder in an upwards position
in the ground, the top level with the surface, would that be a good idea for
trying to acheive a decent RF ground? Also, is there anything I could place
around the cylinder to better the conduction between the cyinder and the
earth around it? Should I drill holes in the cylinder so I can pour water
into the cylinder to keep the ground around it moist?

Would I still benefit from some radials in the ground?

My garden's about 33 foot long, 21 foot wide. Ground gets rather rocky and a
bit sandyish at about 9 inches or so from the surface.TIA.