So, that was officially the coldest December for 13 years. Actually I think it might be a bit longer than that – I can just about remember 1996 and I’m sure four weeks solid of ice, sleet and snow would have registered. But anyway…. it’s cold. Very, very cold.

Gardening outside is more or less off the agenda, of course, so I’ve largely retreated into the greenhouse. To cheer myself up I’ve given myself a little challenge: I want to try to grow really, really big onions.

Actually I’m a bit late out of the starting gate already: the traditional time to sow competition onions is Boxing Day, but I spent my Boxing Day nursing a hangover and refereeing small children fighting over skateboards and Nintendo DS’s so onion-sowing was a little low on my list of priorities. Anyway, I  figure as it’s my first attempt I’m hardly likely to sweep the board and a week or so here or there won’t matter too much.

Exhibition onion growing is a sport which doesn’t have devotees so much as obsessives. If you want to see just how far people are prepared to go to produce the fabled ten-pounder onion, take a look at the allotment diary of this dedicated Yorkshire grower: he puts little plastic collars on sticks around the growing seedlings to keep them upright, for heavens’ sake. So far he’s managed 6lbs 10oz, which in my book is pretty damn impressive. And then there’s John Sifford, from Halesowen in the West Midlands, who in 2005 broke the world record with a bulb weighing a little over 16lbs 8oz. He’s not giving much away, but it’s telling that all the champion exhibition onion growers seem to grow their onions under glass and in containers. Hmm…

I doubt I’ll reach quite those heady heights, but to give myself the best possible start I’ve been taking lots of advice from the past master of such things: Medwyn Williams, who has forgotten more than I will ever know about growing onions from seed and has an MBE and ten Chelsea gold medals to show for it.

The first secret of success with exhibition onions, he says, is choosing the right variety. Onion showing is an ancient art, and the very best varieties have proved themselves over many, many decades. Truly dedicated onion growers develop their own strains from particularly large specimens they’ve grown: but they’re all derived from old favourites like The Kelsae, Ailsa Craig and of course Bedfordshire Champion, which is the one I’ve gone for on my first attempt.

Medwyn says you need to sow into modules of good-quality multi-purpose compost – brought into the greenhouse in advance so it’s warmed to air temperature (this I did yesterday – not that the greenhouse is very warm, but at least 2°C above is better than the -5°C outside).

Then once the seeds have germinated, you prick them out while still at the hooked-over hairpin stage and pot them on religiously as soon as they need it (apparently the longer they hold onto that little black seed case at the end, the happier they are).

Medwyn uses artificial light and heat to get them through February: this may be a bit beyond me, so I’ll just have to cross that bridge when I come to it. Right now, I’m just hoping my little seeds will germinate OK and make it through this punishing weather in one piece.

I’ll bring you progress reports as the year goes on. The village autumn show is in September, so I’ve got nine months to get it right – wish me luck!