The society also wants to increase apprenticeships from eight to 22 and improve its four gardens, at Hyde Hall, Rosemoor, Wisley and Harlow Carr as well as revamping its Vincent Square headquarters. It also plans a salary benchmarking review which might see an increase in horticultural staff wages.
RHS director general Sue Biggs said: "This is a landmark moment for the RHS. As a charity we are careful with our funds and invest them when we believe the time is right. We have turned around a trend of declining members and visitors, and today are in a strong position after several years of growth, with membership and garden visitors at an all-time high. After years of planning, we are now confident to make this significant investment and increase our work to further help and inspire the millions of people who garden in the UK today.
"This 10 year Strategic Investment Programme substantially expands the scope of our existing Key Investment Projects (KIPs), to increase our charitable work and support the future of horticulture for years to come. Two years ago we announced our five-year investment plan of 10 KIPs with a budget of £27m, financed by £18m from the sale of the lease of Lawrence Hall and £9m from fundraising. We are now increasing our fundraising target to £20m over the next 10 years, with the remaining £80m to come from the RHS.
"We've already made some significant progress with our KIPs, including the recent launch of our new website, new horticultural content at Hyde Hall and the development of designs for the new Learning Centre at Hyde Hall, the redevelopment of Lindley Library & Hall at Vincent Square and the new Science building and entrance and retail facilities at Wisley.
"Our new expanded ten year programme builds on these and will see us investing in projects that will make a real difference."
RHS president Sir Nicholas Bacon said: "Some 210 years ago our founders changed the face of horticulture forever when they met in a small London bookshop and resolved to start a Society to further the encouragement and improvement of the science, art and practice of horticulture.
"The commitment we make today is no less momentous and will see us taking their original vision out to more people and places than ever before.
"The RHS is the strongest it has ever been and, after careful consideration and planning, the Council and I are confident that it is time to look to the future."