The quality of what you put on your salad matters just as much as what you put in it.

Don't you sometimes wish that you could collar the chef who has just prepared your restaurant meal and ask how something or other is done; some smart trick that has tickled your tastebuds?

For me, especially at this time of year, it's nearly always salad dressing that brings on this desire to corner the man or woman in whites, a nagging sense that the unctuous liquid covering the leaves and other vegetation in any halfway-decent restaurant salad is noticeably superior to the oil-and-vinegar concoctions I mix at home. My library of cookbooks from Nigel to Nigella – by way of Jamie, Hugh and Delia – stresses how easy everything is: "mix one part wine vinegar to three parts olive oil" and all that jazz – but somehow the results are never quite the same as when you visit the top pros to eat.

"Generally I think the reason why people come up to chefs in restaurants and say: 'Your dressing was fantastic' and ask how they make them is that they tend to be emulsified," says Tom Pemberton of Hereford Road restaurant in London's Notting Hill – meaning the dressing, not the people, tend to be emulsified. No drunks here. But hold the emulsification, Tom. Diners actually come up to you and ask how you make your dressing? Yes and not just the eating public, either, adds Matt Cranston, head chef of the Anglesea Arms in London's Hammersmith, one of the oldest and consistently best gastro-pubs in the country. "My mum is obsessed with dressing. What am I now? 40 years old. For the past 30 years she's been asking me how to make salad dressing and she still can't do it."

Readers will understand my game now. Lacking brazenness as an anonymous diner, I'm using the cloak of journalism to beard top chefs in their lairs. Along with Tom Pemberton and Matt Cranston, Rowley Leigh of Le Cafe Anglais in London's Bayswater, and Yotam Ottolenghi – the Israeli-born veggie king – have been enmeshed in my quest to nail the perfect summer salad and how to dress it. The only trouble is that they disagree on the ingredients, or at least on some of the ingredients. My panel of experts are united in one thing, however, and that is salt. We civilians, on the highly understandable grounds that a salad – if nothing else – ought to be healthy, simply aren't using enough of the white stuff. "Chefs tend to season things quite highly – more so than at home – and when people go to restaurants they think: 'Oh that's tasty'," says Pemberton, while Rowley Leigh, in a simple answer to my simple question about the difference between the dressings one tastes at home and in a restaurant, replies: "The salt, probably." I dip my finger into the dressing that Cranston is whisking together for a goat's cheese salad and it does seem extraordinarily briny to me – but then Cranston is simultaneously sparing with the amount he applies to the salad.

"It's important not to use too much dressing," he says, as I have flashbacks to the Total Wipeout-style dunking to which my lettuce at home is habitually subjected. But just when I'm feeling that I could prepare salads like this myself and live beyond middle age, Cranston then adds salt to raw salad leaves. "People don't season while they are cooking," he says, catching my look.

"They only season afterwards, which is a completely different thing. If you season while cooking then it draws flavours out." Add salt at the end, in other words and you're only tasting salt. In salads, says Leigh, sodium chloride should be the first ingredient into the bowl.

"It's crucial that you dissolve the salt in vinegar before you add the oil, because salt doesn't dissolve in oil," he advises. "First thing I do, automatically, when I make a dressing, is put salt in a bowl, and then vinegar, possibly mustard, possibly sugar, possibly garlic – all those things I'll smooth to a paste before I start adding the oil."

Our chefs differ as to their preferred vinegars, although all agree that it should be of the finest possible quality – leave the industrial malted variety to the fish and chip shops. Ottolenghi says he likes to use champagne vinegar, while Cranston prefers red wine vinegar and Pemberton sometimes likes to uncork the tarragon vinegar. They are no more unified about the oil, except to stress that it is the very last thing to go into the mix.

While Cranston and Leigh belong largely to the olive oil brigade, Ottolenghi argues that this can be too harsh in a leafy salad and advises a more neutral vegetable oil such as groundnut or sunflower.

"I think using olive oil is quite a risky business," says Ottolenghi. "It tends to be quite heavy and dominant. I keep the olive oil for more hardy salads – one that mixes up legumes... you know... beans, or a grain or a lentil." Leigh concurs: "I would agree that in a classic French vinaigrette I would usually mix half and half – olive oil and sunflower oil. But it depends on the use: with tomatoes you want the strongest possible oil you can get. You can't beat sliced tomatoes with new season olive oil."

Cranston is a firm believer in the olive variety. "It has to be a good quality," he stresses. "Although it doesn't have to be one of the supersonically expensive Ligurian, super-fandango, early-pressed, peasant-filtered oils. But get away from vegetable oil – its texture is a bit claggy and it just doesn't add anything to the whole experience."

Last weekend I tried putting some of this at times conflicting advice into practice when I dressed a simple green salad. Into a mixing bowl I dropped a couple of tablespoons of Dijon mustard, onto which I forced myself to sprinkle more salt than I usually would, before mixing in some expensive Edmond Mallot Burgundy white wine vinegar I had bought on an extravagant whim a few months back and never opened, mainly because I never thought I had a suitably luxurious use for it. Now I know this should be my everyday salad vinegar.

Finally I whisked in the Puget brand olive oil that I buy in bulk whenever I visit a French supermarket (along with Bonne Maman jams – they are a lot cheaper across the Channel), and dampened the whole thing down with splashes of cold water, just like I saw Pemberton doing in the kitchen of the Anglesea Arms. And I have to say that it was the best home-made salad dressing that I have ever made. My wife agreed with me.

At the start of the process I could have added a clove of garlic or, preferably, according to Ottolenghi, a shallot. I might have sprinkled in some cayenne pepper, or some sugar to give it that Heinz Salad Cream sweetness (properly made salad cream is making a big comeback, apparently), or honey or lemon juice. Plenty of time to experiment now that I feel I have the magic base dressing.

But what sort of salads should we be making now that proper, barometer-busting summer is upon us and British-grown vegetables are in plentiful supply?

"Really fresh stuff right now are peas, radishes, baby fennel, herbs, new potatoes, the soft lettuces," says Pemberton. Leigh adds: "I've got a very nice salad, which is just raw fresh peas mixed with chopped cos lettuce and I mix that with lemon juice and olive oil, with grated parmesan on top." Sounds good, but what is the best way to mix and match salad ingredients? Can my usual practice – open the fridge and bung in everything that comes to hand – ever be a recipe for success?

"Only if you are willing to bear the consequences," says Ottolenghi. "Even something that looks easy to prepare needs to have the right balance in it – acidity to sweetness, or acidity to saltiness. The same applies for textures. At the moment I have a salad of faro – which is very close to barley – and marinated red peppers and feta cheese. Then I mix in leaves. So what you get there is the significant sweet flavour of the marinated peppers, the faro gives it a beautiful crunchy texture. You get a lot of excitement in one dish."

"I do think people just look in their fridge to see what they've got, chop it up and throw it in," agrees Leigh.

"At home people tend to think that salad is a sort of compendium – you can put anything you like in and it'll be all right, whereas one needs to exercise quite a lot of editorial control."

Four desert-island summer salads

Yotam Ottolenghi

A very difficult question. In my salad there would be artichoke, an aromatic and beautiful vegetable that no other vegetable comes close to (cook it with lemon juice and coat it with olive oil so there is lubrication going on). I'd probably have peas or broad beans in there, because that adds all that extra freshness. I'd definitely have some herbs – probably mint... and coriander, one of my favourite herbs. I would definitely have some citrusy flavour – in this case lemon juice. If I wanted to make it a little bit more substantial I would add boiled whole wheat grain.

Tom Pemberton

It might be a warm salad – not very English, I know – which a chef I used to work with a long time ago used to make using chorizo, salad leaves and new potatoes he cooked in chorizo fat, which them went bright red. And then he'd make a salad of that, using bacon lardons, and often he'd put a few grapes in it. I can't tell you how delicious it is.

Rowley Leigh

One of my summer classics is white peach and tomato, absolutely delicious. Just peel the tomatoes, peel the peaches, cut them into segments and toss them in olive oil, salt and pepper and basil. Very simple. A friend of mine lives in Venice and she entered a salad competition last summer and she won the competition with my peach and tomato.

Matt Cranston

I'm a big fan of good old-fashioned, what I call 'floppy lettuce', like butter lettuce, which I use at the pub when I can. It reminds me of being younger at home and I just think it's something we don't use enough any more. To me it just says summer. I serve it with peas and radishes and salad cream and croutons.