He launched two-year educational project Acorn Grows on 27 November by planting a young oak tree at Crookhey Hall in Lancashire, a school for boys with social, emotional and behavioural difficulties. It is one of 13 run by Acorn Care & Education.
Frost will help them develop an area of the school into a wildlife garden and give a series of lessons at Crookhey and other schools from Cumbria down to Cornwall.
He said: "At all the Acorn schools I have visited, the staff’s passion and commitment and what they have shown me has been unbelievable. Their total dedication towards what they want to do for these young people is extraordinary."
"I just want to help some of these amazing children and I want to support the staff. If I can encourage even one more of these kids to come into our industry through my involvement with them, that’s cool."
In his first lesson - which included surveying, soil testing and an introduction to design - he treated the boys to a sneak preview of his 2014 RHS Chelsea garden design.
The company is also launching an apprenticeship scheme to offer its most promising students a help on to the first rung of the career ladder.
He has already helped his RHS Chelsea Flower Show sponsor, Homebase, develop a separate apprenticeship scheme which has seen the first intake of apprentices within the past few weeks.
Crookhey Hall pupil Carn who joined the school after being permanently excluded from mainstream education is one of those inspired by Frost.
He said: "This is a brilliant project for me because I was seriously considering a career in horticulture anyway and this has made up my mind. I’d like to be a landscape gardener and Adam has talked to me about how he started and worked his way to the very top of his profession."
Head teacher Robin Adams said: "Horticulture is already a popular subject on the curriculum here, and it’s wonderful to have someone like Adam involved. He has already inspired the boys and the staff are loving his involvement and expertise."