And up. And up.

Unless you grow the veg yourself. Luckily there is one veg that you can plant now and have a crop within a month, and if you plant enough, will still be eating it next spring, when you can bung in another crop. It's lettuce, or as the school yard joke of my childhood went, ''Honeymoon Salad: Lettuce Alone Without Dressing''.

Lettuce alone (though with a good dressing) can make a most excellent salad. One Buttercrunch lettuce is perfect for one person, or possibly two Buttercrunch if you are greedy (I'm greedy). The tragedy of Buttercrunch - possibly the world's sweetest and most tender lettuce - is that once you have picked its soft heart and crisp outer leaves, that's the end of it, unless you are a wallaby or possum. If you leave Buttercrunch's root and stem it may well grow a few more leaves, but they'll be bitter.

I rarely recommend a commercial product, but if you love salads of mixed young leaves, there are some brilliant new varieties around, like Salanova Lettuce Red Butter or 'Red Crisp' or 'Green Butterhead' or 'Green Crisp'. All of them can be harvested leaf by leaf. You'll get tiny leaves within a month, and full-grown ones a fortnight later. Keep picking and the leaves will keep growing IF (and this is a major 'if') you feed your lettuce at least weekly, and water them daily. Lettuce are mostly water, so one day of heat can leave them limp or even deceased. Even a single lapse in lettuce cosseting may also turn the leaves as bitter as a political candidate who failed pre-selection.

Mulch well to prevent extra heat reflecting from the soil, and place a few containers of slug and snail bait on top of the mulch. Slugs adore lettuce, and if you don't wash your home-grown lettuce carefully you may find that your lettuce salad is a slug and lettuce salad, which will impress neither you nor the slugs, nor any visitors you have intended to share your home-grown bounty.

Don't scatter the bait, as you may kill more than the slugs. Pour the bait into any container - milk bottle, butter pack etc - where you can cut a couple of small snail and slug sized holes in the base, then wriggle it well into the soil so that the slugs and snails will have a ramp to get into the trap to eat the bait. Slugs and snails do not like getting their tender tummies scratched by the edge of a container.

If you don't feel like slaughtering snails and slugs, you can use this slug and snail sensitivity to advantage by asking a friendly hairdresser for a bag of hair, preferably well chopped - a gentleman's hairdresser is perfect. The hairs can be scattered on top of the mulch among the lettuces, thus making the area inhospitable to any slug or snail who ventures near, as the ends of the hair will irritate them. Shell grit is another slug and snail annoyance. Sprinkle small fences of it about the garden to stop slugs and snails encroaching.

There are many, many other leafy salad veg you can plant now, too. Henry VIII had his own Keeper of the Royal Salad, with up to 56 ingredients per Tudor salad. I've failed to come up with 56 salad ingredients available to the royal court back then, and there are a few, like nasturtium leaves, I'd rather leave in the garden, away from my salad bowl. But Corn Salad is a good one, best planted here in early autumn to mature and be harvested in winter. Corn Salad can turn bitter in hot weather, but is sweet and nutty in the cool.

Rocket is another, but modern varieties are far less bitter than the one back in Henry VIII's day, though his gardener possibly blanched the otherwise bitter greens by covering with soil or straw to make them pale and tender as well as sweeter. Rocket is extraordinarily easy to grow, and an excellent addition to autumn, winter and spring salads. It can also add welcome bite to summer salads, and goes exceptionally well on a cheese sandwich at any time of year, when it's sharpness is mellowed by the bread and cheese.

You don't need a garden to grow cut-and-come-again lettuces. Two large pots and tender care will give you enough to harvest three times a week in warm weather, and through winter if you have a hot patio or roof garden that catches the sun.

And your crop will be very cheap indeed. A packet of the most upmarket lettuce seed will set you back about $6. Some sources sell their seed for as little as $3 a lot of seeds. As long as the seed has been well kept, you could get almost 100 per cent germination - and fast, too, though slugs and snails can be far faster than you might imagine and can consume a garden's worth of lettuce seedlings in a night. You have been warned.

But if you have the water, plant lettuce now. You'll get a massive crop for less work than it takes to collect a plastic covered lettuce in the supermarket and then wait in the checkout queue. Given adequate care, your home-grown leaves will be delicious, so fresh and sweet they need no extras, except perhaps some dressing.

My Current Favourite Dressing

A pinch of salt in the base of a large salad dish. Add 1tb extra virgin olive oil and a teaspoon of the best white wine vinegar you can find. You don't need much, so you can be extravagant. Place enough leaves to fill the bowl on top, and toss with a couple of forks. Salad dressing shouldn't drown the leaves or they'll go limp, just coat them super lightly to give succulence to the most perfect (and hopefully slug-free) summer salad.