Best on earth: It's time to get serious about your spuds

Need a potato to help you lose weight or one you can grow in a bucket?

So, potato-fair season is in full swing. And you thought life in February was to be dominated by conversations about Kate Winslet's possible Oscar outfits... Come now, potatoes are so much more fascinating.

The big potato push – with accompanying potato fairs – is because this is just the moment to be planning your 2009 spud planting. These fairs, held in school gyms and town halls across Britain, allow growers to trade and buy "seed" potatoes – tiny baby spuds – so you can pick the right varieties for your plot. Most fairs offer a chance to browse up to 100 different seed potatoes, as well as providing an opportunity to talk to people who've actually grown the spuds, about how they perform – a real advantage over most order-taking websites.

Beginners hoping for a plateful of delicious new spuds from a patio bucket will get best results with potatoes called "first earlies" or salad varieties, which will grow better in a pot than maincrop potatoes. Good "early" varieties include Foremost, Anya and Charlotte, and if you buy a Gro-Sack from Marshalls (£13.75, www.marshalls-seeds.co.uk) you get 15 seed Charlottes free. Those with back-garden beds and allotments have more choice, and can try growing big maincrop baking potatoes such as the classic King Edward or the disease-resistant Sante.

Most people at a potato fair plump for the old favourites and there's often a frenzy for Desirees and King Edwards. But there is also a strong contingent of heritage-variety lovers, who take it slow, browsing spuds from the days of yore, clutching like limpets to the babies you have your eye on.

Should you actually want to get into a Kate Winslet-style Oscar outfit, keep an eye out for Vivaldi (three-kilo packs, £6.95, from www.suttons.co.uk). Before I had tasted it, I thought that claims to have bred a potato with half the calories of any other were probably, well, sales hype. Especially the promises that the potato had such a creamy taste that it required less butter when eaten (almost always my downfall).

Naturally Best, the Lincolnshire firm that bred Vivaldi, spent nine years getting the carb and calorie count so low. Announced by the BBC with the headline "Scientists make 'slimming' potato", Vivaldi has increasingly made its mark on supermarket shelves, and now Marks & Spencer sells it in its luxurious vegetable line – surely the ultimate mark of posh-food acceptance.

However, the truth is in the tasting, and this potato is completely delicious, with soft, sweet, golden flesh that's genuinely melty. And it really does need loads less butter. A potato for people who shouldn't really be eating potatoes: how much better does life on a diet get?

Go to seed: Pop in to a potato fair

Today: Gordale Nursery, Cheshire

Ten-time Chelsea Gold medal winner Medwyn Williams gives tips. www.gordale.co.uk

Today: Hove Town Hall Seed Swap,10.30am-4pm

Britain's oldest established day of swapping with flowers as well as spuds. www.seedysunday.org

Saturday 7 February: Pylle Church Hall, Shepton Mallet, Somerset, 10.30am-3pm

The local nursery Pennard Plants' fair with spuds, seeds, onion sets and shallots

Saturday 14 February: East Anglia Potato Day, Stonham Barns, near Stowmarket, 9.30am-2pm

50 different potatoes on sale. www.eapd.btik.com

For other potato-related events see http://tinyurl.com/cld5ne