Potatoes: dark and cool, never cold
The single most important thing for potatoes is darkness. Light — even the ambient light of a kitchen — triggers the production of chlorophyll and solanine, turning the flesh green. Small green patches can be cut away generously before cooking, but a potato that is extensively green throughout is better discarded. The greening is the plant's defence chemistry, not a cosmetic issue.
Potatoes also need cool air — a cellar, an unheated porch or a dark cupboard against an outside wall all work well. A hard frost converts the starches and makes the flesh unpleasantly sweet, so avoid anywhere that drops below freezing. A breathable paper or hessian sack is better than a plastic bag, which traps moisture and speeds rot. If you can only find them bagged in plastic, decant them as soon as you get home.
Guidance on refrigerating potatoes has shifted in recent years. Check the current Food Standards Agency advice rather than relying on older received wisdom — the FSA's website is kept up to date.
Onions and garlic: dry and breathing
Onions and garlic need almost the opposite of what potatoes need. Moisture is the enemy. Both keep best somewhere dry and airy — a well-ventilated rack, an open-weave basket, or a traditional string or plait hung in a cool room. A dark spot helps, but airflow matters more.
Onions and potatoes should not share a storage space. Onions emit gases that accelerate potato sprouting; potatoes give off moisture that softens onion skins. Separating them makes a real difference to how long both last.
Garlic dislikes the fridge — cold and damp together encourage sprouting. A loose-weave bag or small terracotta pot on a kitchen shelf works well for a bulb or two in regular use.
Carrots, parsnips and beetroot: cool and slightly damp
Root vegetables want cool air with a little humidity — the opposite of what onions need. This is why they kept so well in a traditional clamp, buried in damp sand or earth. At home, a vegetable drawer at the bottom of the fridge, or a cool pantry, is a reasonable substitute.
Remove any leafy tops before storage: the leaves keep drawing moisture from the root long after harvest. Leave a short stub rather than cutting right to the crown. Carrots and parsnips that have been washed deteriorate faster than unwashed ones, so hold off scrubbing until you need them.
Beetroot behaves similarly, though it tolerates slightly warmer temperatures than carrots. Any showing signs of softening are still usable — cook them sooner rather than later.
Squash: the odd one out
Winter squash — butternut, Crown Prince, delica and their relations — have very different requirements from the rest of the veg rack. A newly harvested squash benefits from a period of curing in warm, dry conditions, which hardens the skin and extends shelf life considerably. Once cured, squash keeps for months at cool room temperature, which is warmer than root vegetables prefer. A cold, damp cellar is not ideal; squash wants somewhere dry, with gentle air movement, away from frost. We have a longer piece on curing and storing squash in this journal for the full detail.
Buying loose makes a difference
Loose vegetables, bought from a farm shop, market or greengrocer, almost always keep better than pre-bagged equivalents. Plastic packaging causes sweating, and by the time you open it there may already be soft spots or early mould developing unseen at the bottom of the bag. Buying loose also lets you inspect each piece and pick around anything already compromised — a small habit that adds up over a whole season's shopping.
