The producer of a major new TV series describes it in the following terms: "They are fighting for a place, all they want to do is have sex and take over the world". Goodness, you think, this must be a bonkbuster addition to the late night schedule on Channel Smut, or Channel 5 to give the official name.

A further clue is the star - gardening guru Alan Titchmarsh, a man with a reputation as a heart-throb among ladies of a green-fingered persuasion. Fans have been known to throw articles of underclothing at him during personal appearances, and one of his fiction books won a best "bad sex" prize.

But I must spoil their image of Mr T wearing nothing but a pair of garden gloves and brandishing a pair of secateurs. He only gets dirty in a gardening sort of way in BBC2's How To Be A Gardener. Series producer Kathryn Moore, who's worked on BBC documentaries for over a decade, was the one putting the sex slant on the Beeb's most ambitious gardening programme yet.

It's tempting, for those who like pursuing a gardening analogy, to state that Titchmarsh is going back to his roots. Certainly, he's dealing with the basics of how and why things grow. If Delia Smith can do it in the kitchen, telling everyone how to boil an egg, there's no reason Titchmarsh can't do it in the garden. "It assumes no gardening knowledge at all but is also aimed at those just coming into gardening," he says. "I think it strikes the right note for everybody. I really hope it makes viewers want to get out there and garden."

It certainly worked for Moore, whose past TV work includes Life Of Grime, the series about environmental health officers, and Ray Mears' World Of Survival. One look at her courtyard garden at her Bristol home will testify to that. "Before I started this series, it had a lot of things that were dying. Now it has plants that adore being in a slightly damp, small, dark courtyard," she says.

The idea for the back-to-basics series was Titchmarsh's. As someone who knew nothing about gardening, Moore is there to represent viewers.

"He's wanted to do something like this for about the last five years," she explains. "The first programme is about why plants grow the way they do and what exactly is going on in your garden. If you understand why something works, which plants work the way they do, you're much more able to translate those facts into a wider context.

"You think your garden is a harmonious place to be and it's natural, but it's the most artificial place you can find. Most of those plants have never met in the wild. They're all fighting for a place, all they want to do is have sex and take over the world."

Her task in the series was to ask Titchmarsh "the really stupid questions" that people sitting at home want to ask. Questions, she says, to which you think you should know the answer but are too afraid to ask. "He said it was like working with a child because I kept saying, 'why?'," she says. "Plants want to grow and thrive and make as many babies as they can. If you give them the right conditions they will do what they've always wanted to and that's survive."

The gardens featured in the eight programmes are in Hampshire, the county in which Titchmarsh lives. They were found through gardening clubs and appeals through big companies in the area. Moore says that specific types of garden were required for the topics the programme wanted to illustrate.

Shooting began in February last year and wasn't completed until last week. Arranging the filming schedule was harder than on other series. "Plants aren't like people - you can't order them to turn up on a specific day and look their best," says Moore.

"You might allocate three weeks on Thursday to film something, then there's a storm or the day is very hot, and you have to rearrange all the filming."

One of the most difficult aspects resulted from the series offering scenes from the plants' point of view. They used special effects techniques created by cameraman Tim Shepherd, who worked on The Private Life Of Plants. Plants wither, grow and blossom before viewers' eyes. Sometimes Titchmarsh stands there while a plant appears to grow next to him.

Perhaps the trickiest scene involved Titchmarsh sitting in a chair on a patio as a weed grows up his leg. This was shot in two sections - the presenter sitting down, then special effects filmed the growing plant and put the two together.

"The cameraman filming the plant had to recreate Alan's foot and the right lighting. He had to make the patio exactly the same, although the original was in Hampshire and he was filming the special effects in a studio in Oxford," says Moore.

"We worked out exactly how we were going to do it - the lighting, where Alan's feet were, everything. Then we realised they'd filmed with the sun coming up from the left not the right as in our film. So we had to shoot the whole thing again."

As for Gardener's World and Ground Force presenter Titchmarsh, she has nothing but praise. "We couldn't have done it without someone of his calibre. He's tremendous," she says. "People say, 'what's he like?', desperately hoping you'll say he's a very nice man. And he is."

*How To Be A Gardener begins on BBC2 on Wednesday at 8.30pm. The book, also called How To Be A Gardener, is published by BBC Worldwide, price £18.99.

Published: 23/02/02