I took my plot on in May, too late for spuds - or so I thought. The 'old boys' all put a new crop of spuds in in JULY 'for Christmas' :o and gave me some hollow spongy leggy seed potatoes left over from the Spring planting. :-\ But since there was little else planted, I shoved them into one of the beds, through holes in black plastic, and threw mulch around them - spent hops, bits out of seed trays, and topsoil - whenever I had some.
Nothing seemed to happen for three weeks. Then they took off about two weeks ago and look healthy and happy.
The 'old boys' will have to tell me what to do when frost threatens. And I don't know if the tubers will grow under or over the black plastic, or a bit of both, so will keep mulching.
This is the first time I've heard of planting in July for Christmas outdoors. Anyone else out there doing it?