Show gardens highlighting the trend include those mixing horticulture and agriculture, as well as growing more unusual crops.
Home Grown highlighted a mix of commercial horticulture and agriculture new to an RHS feature. Designed by Jon Wheatley, Mary Payne and Gillian van der Meer the garden showed traditional and state-of-the art growing in an inspirational setting.
Stonebarn Nursery owner Wheatley's 2,000sq m exhibit highlighted the increasing diversity of fruit, vegetables, cut flowers and ornamentals that can be grown in the UK. It included a model farmland that showcases agricultural Britain and commercial techniques.
Unusual plants showcased include Chinese artichoke, cape gooseberry, oca, Chinese stem lettuce, anu and Sacred Lotus.
Wheatley said: "In Britain we can do as well as anyone else in the world. Very often we don't say how good we are at growing a wide range of plants."
Braeburn apples from Blackmoor Fruit Nursery were on show. Wheatley said it was good that the grower could now provide the New Zealand apple to Marks & Spencer and other retailers. He added that agriculture and horticulture were merging as farms diversify.
He said growing crops such as sweet potatoes and Amaranthus is now possible, rather than importing them. Suppliers included Suttons, RW Walpole, Winchester Growers and New Holland.
Wheatley said exhibits such as Home Grown would raise commercial awareness of new edible and ornamental crops that farmers and growers could pick up on.
He said: "There's nothing I see at Aalsmeer we couldn't grow here. It's time the Government recognised the value of horticulture."
Shakespeare's Allotment at the show featured rare vegetables and herbs including skirrets, winter savory, strawberry spinach and heirloom sweetpeas.
RHS shows development director Bob Sweet said: "Grow-your-own has been a very important area of horticulture for a long time. We thought the bubble would burst but it hasn't."
Seeds of Italy director Paolo Arrigio said that everyone had expected Christmas, outdoor furniture and barbecue trends not to last, but they had, therefore there was no reason why the grow-your-own trend could not be here as a sales category for good. GCA figures show plants are up 1.5 per cent this year and seeds sales have increased by nine per cent.