When we buy supermarket veg, we’re buying not just food but a classification system. Carrots, for example, must be called ‘early’ carrots if they are less than 20 millimetres across the shoulder. An onion is only an onion if more than half of it is covered in onion-skin. It’s important to understand this because ‘early’ carrots in a supermarket are not necessarily the ‘early’ carrots that you’d harvest yourself. They could be a late growing variety that’s been harvested while still small to get them in the shops before slugs (for example) get into them. And that means they don't taste like the first carrots of the year you'd grow at home.

Our grandparents, and certainly our great-grandparents, knew all about seasonal cooking – early carrots were eaten with asparagus, often in a simple white sauce to bring out the flavours. Late carrots were roasted or put into stews. But supermarket carrots lose a lot of their seasonality and tend to taste the same all year round, because, supermarkets seem to believe, we want absolute consistency in our food rather than seasonal variety.

The only vegetable that seems to have escaped this regime is the potato. Everybody knows that the new potato tastes completely different to the maincrop, and most people cook them totally differently too. A new potato always boils well, and needs very little to bring out its flavour: a pat of butter and some cracked pepper are all the support it requires. A maincrop potato may be a baker, a chipper or a boiler and often needs a bit more scaffolding to bring out its best qualities. So when you grow your own, don’t just assume all recipes work perfectly with your freshly-harvested vegetables. A sniff test is good, as it often tells you how rich the vegetable will be in flavour, and when you cut home-grown vegetables with a knife you can learn a great deal about how juicy/fibrous/tough/crispy they are.

Early carrots are full of flavour and are often best eaten raw, but late carrots benefit from some oomph: try scrubbing them and leaving them whole, then oven-cook them in a covered dish with some vegetable stock and a couple of sliced shallots. To serve, grate some orange zest over the top of the dish and let people slice the whole carrots on their plate – recent research shows that this can double the nutritional content as a lot of the nutrients rest in or just under the skin. Very late carrots can be a bit woody, but they are wonderful for carrot cake or for making into soup – to get the best flavour out of soup carrots, bake them for 20 minutes in the oven in a little olive oil before you puree them and add some cinnamon to the soup stock to bring out the warm flavour of the roasted vegetables.

Late lettuce often just gets thrown on the compost heap because it’s gone woody, but you can use it to make a warm wilted lettuce salad that tastes superb. Use an older lettuce for this dish – cut any really large ribs out of the lettuce and then stir fry it very briefly in some walnut oil with crushed garlic and some lemon juice. Lay it on slightly warmed plates and top with a soft goats cheese or some pickled herring. Light cooking brings out the fresh flavour of the lettuce but reduces its toughness.