The daughter of a 'gardening-mad mother, Miller, 32, has only recently felt herself attracted to the horticultural life (Nick was in charge of their Devon garden).
'Sometimes I worry that Im hitting middle age early, she says.
Making up with enthusiasm for what she lacks in time, she has tried to make gardening a family pursuit. To that end, she has designed a new garden at the side of the house, which has been her main focus for the past year. From a terrace featuring a sandpit, tastefully covered with a folding wooden top, steps lead up to her most prized creation: a small edible garden, with a domed willow house for her children (a third is due in November). A pond surrounded by grasses and wildflowers is filled with fish.
The emphasis here is on sustainable living. Inspired by Alys Fowlers BBC series The Edible Garden, in which Fowler attempted to live off the fruit and vegetables from her own plot, Miller planted a vegetable garden, all (with the exception of the berries) grown from seed. A keen cook, she is excited by the prospect of eating what she has grown: broad beans, peas, runner beans, rhubarb, tomatoes, fennel, broccoli and cabbage.
'I dont really know what Im doing so its all a big learning curve, she says, remembering returning from a two-week holiday to find that the rocket and mustard seed had 'majorly bolted.
Determined to eat and live as organically as she can, she does her best to avoid using non-organic pesticides. But she has resorted to using a chemical mildew spray to save a favourite David Austin climbing rose, which is suffering badly in the clay-based Gloucestershire soil, notorious for its bad drainage.
She has not yet found the time to put into action some advice from a friend to make an eco-friendly plant feed by soaking nettles for several days in rainwater. Nevertheless, she is very happy that her bee-friendly flowers lavender, a buddleia and scatterings of meadow flowers are flourishing.
It is a source of frustration for Miller that work and family commitments prevent her from being in her garden as much as she would like. Even weeding oddly, her favourite task gives her a sense of wellbeing.
'It really grounds me, getting my hands in the mud, she says.
'My life is so busy and I can get so frazzled by it. Heading out into the garden always helps me, even if its only for five minutes. It feeds my soul.