Now we know: Why do potatoes sprout?

If your home is too warm the potatoes will assume that it’s spring

October seemed to jump out from behind September and shout “boo!” at us unsuspecting summer bunnies. Sure, we’ve seen the leaves start to turn but the weather has been so temperate that I for one cannot quite believe autumn has arrived. It’s not just me who’s seasonally confused: the spuds in my pantry have been sprouting long, spindly roots. So, why do you potatoes sprout?

Jenny and Patrick McNally are renowned in the Irish food world for the outstanding produce they grow on their organic farm in Balrickard, Co Dublin. The McNally Family Farm specialises in seasonal vegetables and salads, and its customers include Assassination Custard, Meet Me in the Morning, Forest Avenue and The Fumbally. That’s not to mention the customers of their farm shop open at the farm on Friday evenings, or their stalls at Temple Bar food market and Dún Laoghaire’s People’s Park farmers market on Saturdays and Sundays respectively.

Potatoes have a year round yield and it’s currently potato harvesting season at the McNally farm where they are building up their store for the winter. The family grows a variety of potatoes including the versatile Setanta, the waxy Orla, the pink-skinned Alouette, and the dry, floury Belmonda.

“The reason why potatoes sprout,” explains Jenny McNally, “is because if it’s warm, the potatoes can be tricked into thinking it’s spring. People tend to have their houses at a temperature of around 20 degrees, which is the ideal growing temperature for potatoes.”


Brown paper bag

McNally advises keeping your potatoes stored and covered in a cold place, such as a back kitchen, an outdoor shed or even a balcony. Keeping them away from natural light is a good idea, so brown paper bags are helpful as opposed to clear plastic bags.

In actual springtime, the sprouting of the potatoes affects the structure and taste of the potato, says McNally. “They start losing their moisture and they get rubbery. They’re still good to eat but they’re not as tasty. April and May is a good time to take a break from potatoes, before the new potatoes come in July and August.”

The sprouting at this time of year has little effect on the taste and structure of the potatoes, says McNally, so just knock the sprouts off and keep cooking.