On Thursday, January 4, 2018 at 11:30:14 AM UTC, Charlie Pridham wrote:
On 04/01/2018 10:17, stuart noble wrote:
Based on my observations over the years, I intend to support my newly acquired grapevine with 4" x 2" posts bedded in fine gravel. They always rot at ground level, so maximum drainage for the first 6" or so would seem to be the key to post longevity. Well, at least you can yank them out easily enough when they do rot. Anyone any comments? Metposts are not really approved of by the allotment establishment!

Metpost are rubbish and rot out just as quickly as wooden ones, use
decent tanalised posts and when they start to go bang in grandfather
posts next to them.
A lot depends on the ground conditions

--
Charlie Pridham
Gardening in Cornwall
www.roselandhouse.co.uk

I'm not sure "tanalised" means much any more. I saw a piece of 9" x 9" rot halfway through in something less than 5 years. Mind you, it was up against soil all along its length. The makeover merchants appear not to have a long term view.