Spring's eternal

Food shopping in our house goes something like this. I do it, and then my boyfriend comments on it. "Where did you buy these?" he will ask of my apples/runner beans/ strawberries. I will answer, but it is never the right answer, because a few moments later he will say, "You know, strawberries from Peru/ China/the Antarctic are not a good idea. We're not meant to eat strawberries in December." Further comment will come when we eat them: "as tasty as ice cubes" will be the verdict.

Food shopping in our house goes something like this. I do it, and then my boyfriend comments on it. "Where did you buy these?" he will ask of my apples/runner beans/ strawberries. I will answer, but it is never the right answer, because a few moments later he will say, "You know, strawberries from Peru/ China/the Antarctic are not a good idea. We're not meant to eat strawberries in December." Further comment will come when we eat them: "as tasty as ice cubes" will be the verdict.

I used to know when produce was in season because when I was a child we bought much of our food locally. But somewhere between circa 1975 (when self-service fruit and veg became the norm in supermarkets) and now, it's all gone wrong. Our gastronomic wallpaper is always colourful, but rarely changes: like one big global season. There are always plums, berries and bags of salad; we never go into a supermarket to be told there is no lamb or fish.

In recent years, the seasonality of food has been lost rather in the deluge and growing popularity of organic produce. Organic farming may have solved one problem - the use of antibiotics and pesticides - but it has nothing to do with eating seasonally.

The first thing to remember is that to truly eat seasonally you need to eat food that hasn't travelled 12,000 miles to get to you. The criteria for farmer's markets (the very best place to buy seasonal food) is that food is as local as possible; it must have travelled no more than 100 miles but often comes from much closer. Research published last month from the University of Essex and City University showed that buying locally produced food would save the UK £2.1bn in environmental and congestion costs.

Nina Planck, author of The Farmer's Market Cookbook, has a word for it: "Slocal". "'Slocal' is my coinage for food that's slow [allowed to grow naturally and sustainably], and local. When shopping for produce [fruit and veg], I always favour local and seasonal over organic. I'm seldom concerned when buying direct [from the farmer] that it's certified organic. Local and seasonal food is fresher and tastier. I also favour better-tasting varieties picked at perfect maturity. That means I seldom buy any imported produce that can be grown in my region."

The main problem, as with so many of our food supply issues, is that supermarkets are only interested in profit. While a label will declare a food's provenance, if you shop online, as an increasing number of us do these days, you can't see the label and the country of origin is not always declared. Furthermore, what information they give can, at times, be misleading. Doing a recent web-shop with Waitrose (the most socially conscious of all our supermarkets), it declared words to the effect of "the English apple season is now over and the New Zealand one is about to start". So I was rather surprised to still find apples at my local farmer's market.

All of this rather stems from our impatience, and nothing better represents this than tomatoes. We all complain that our tomatoes are tasteless, but what can we expect if we want them all year round? The season is, roughly, August to October. Tomatoes need soil and sun, but these days they are grown without soil, hydroponically (in a water-bath) so that they develop more quickly, with less risk of disease. They also have thick skins that travel well but do nothing for the quality. The temperature and atmosphere are artificially controlled and what little ripening they're allowed to do while still attached to the plant is artificially induced, using ethylene gas.

The picking is also a skill: the tomato needs to ripen on the vine but finish its journey on your window sill or table-top (never in the fridge). However, supermarket tomatoes are plucked from the vine way too early and chilled to be transported thousands of miles. So we end up with something that looks like a tomato but tastes of nothing. What we've forgotten is that the soil imparts a huge amount of local flavour, but our tomatoes have never seen earth.

Soft fruits and berries have suffered the most in having one continuous "global season". Picked at perfect ripeness, the night before eating, and sold locally, a strawberry, blackberry or plum will have the maximum amount of natural sugars and be bursting with sweetness. But picked long before maturity, chilled and transported many miles to sit forlornly in our fruit bowls, such a fruit will deliver little pleasure. Peas and beans that aren't eaten quickly will have most of their sugar turn to starch, which is why frozen vegetables can actually be more nutrient rich than fresh produce that has sat around for days. The ironic thing is that green vegetables, eaten at the right time, are actually so deliciously sweet, few children would have to be coerced to eat them; but it's a lucky child that gets to eat broad beans straight off the plant.

Meat and fish, too, have seasons - although our staples of beef, chicken and pork are truly available year round. The seasons usually serve to protect a species during their spawning/ breeding seasons. A good thing to do here is buy when something is in season and freeze it. Many soft fruits won't freeze well, but protein does. (The exception being oily fish such as mackerel - the high oil content doesn't lend itself to being frozen.) A word about wild Atlantic salmon: the season is April to September. The spring fish is superior in taste but its numbers have dwindled to critical level, so if you must eat it, it's best to have an autumn fish as they aren't so scarce.

This doesn't mean never being able to eat lemons, mangoes, bananas, avocados or anything else not locally grown. Surely the benefit of being a global community is that we can have some exotic variety - if we want it. "One paradox of the modern supermarket, which provides all foods from all over, 365 days a year," explains Planck, "is what I call the food rut. Faced with total choice all the time, people eat the same couple of fruits and vegetables all year round. They become blind to the (unchanging) choice and fall into a food rut. But when you shop seasonally you eat more diverse foods, even when choice is limited in any given season. "

I now buy all my fresh produce from our local farmer's market each Sunday (well, almost - I still like my mangoes). It is so much fun, and I can talk to the growers and farmers. Lettuce is freshly picked and not washed with chlorinated water, and the pig farmer brings me extra-thick cut bacon, as I like it. At the moment, there is excited talk of asparagus, the new "green gold". The first shoots, properly grown in earth, should be on sale soon. I can hardly wait.

When should you look out for your favourite locally produced food?

We're in 'The Hungry Season' at the moment, but you can use this list to check when your favourite foods are at their best - and maybe try something new...

Spring (March-May) Outdoor rhubarb, asparagus, rocket, brown crab, lettuce, spinach.

High summer (June-July)

Beetroot, garlic, peas, turnips, elderflower, new season lamb, mackerel, tomatoes, broad beans, cucumber, aubergine, courgettes, fennel, cherries (July only), blue-berries, red and black currants.

Late summer and early autumn (August-September)

Blackberries, wild mushrooms, sweetcorn, tomatoes, elderberries, plums, raspberries, goose, celeriac, brussel sprouts, cabbage, leeks.

Winter (October-February)

Apples, squash, pumpkin, cauliflower, pears, grey partridge, red cabbage, parsnips, pheasant, venison, turkey, swede, kale, hare, carrots, onions, chestnuts, eels.

For further information, visit: www.farma.org.uk; www.lfm.org.uk; www.freshinfo.com