The girls will be 18 on Sunday
The Waltons are appearing in a special BBC One documentary on Wednesday, ahead of their birthdays this Sunday.
Mrs Walton, 49, said: "We have always encouraged the girls to be individual.
"Some of them are more outspoken than others.
"It would have been easy to lump them all together but we didn't."
After-dinner speaker
Her husband has even developed a sideline in after-dinner speaking on what it is like to live in a household of seven women.
But with all the girls still living at home Mr Walton said it would be sad if they decided to move out in one go as the house would suddenly fall quiet.
The sextuplets' arrival in 1983 came as a surprise to the couple, who had been tried for a baby for five years.
They had been told it was unlikely they would be able to have children.
The Waltons had just been accepted as adoptive parents when they were told they were expecting six children.
In Wednesday's documentary, Mr Walton will speak about the couple's decision to tell their story to the media.
After the girls were born, he took a year off his job as a painter and decorator to help look after them.
Mr Walton, 51, said:"All of a sudden we went from nothing to six babies.
"We had to work our plan, what we were going to do to look after the babies, how we were going to get money to keep and we did our best.
"If we made a mistake, we made a mistake.
"There's no manual how to do these things and we did our best."
Media deals
But his wife told BBC Breakfast they did not get as much from sponsorship deals as might be imagined.
The documentary will also show the different career paths their daughters Hannah, Lucy, Ruth, Sarah, Kate and Jenny were pursuing.
Lucy wants to be a TV presenter or a model.
"I have always wanted to be famous. I don't know why," she said.
Hannah hopes to do a business degree after her A levels.
Her sister Kate is also taking A levels, with a view to doing a media and cultural studies course.
Jenny, who finished her GCSEs last year, is currently unemployed.
Meanwhile Ruth dreams of running her own nursery and is doing a child-care course.
Sarah works at an insurance firm in Liverpool city centre.
The family have already been on holiday to Majorca to celebrate and will have a special lunch on Sunday.
The Walton Girls Come of Age is on BBC One on Wednesday at 2055GMT