Members of the Huddersfield Giants Community Trust National Citizenship Service (NCS) spent a week at Thornhill Care Home to carry out the work.
They created plant pot borders around the home’s garden, installed solar lighting and laid artificial turf.
The 15-to-17-year-olds held fundraising activities and appealed to local businesses for supplies.
They also received funding from Kirklees Council, after support from Councillor Sheikh Ullah, to purchase benches for the home’s residents.
Mayor Councillor Gwen Lowe, Deputy Mayoress Noreen Lowe During and Councillor Ullah attended the official unveiling of the garden at Thornhill Care Home, on Thornhill Road.
Johnny Edwards, home manager of the Hill Care Group operated care home, said: “We are so grateful to Huddersfield Community Trust NCS for choosing Thornhill Care Home for their community project.
“The work they have done in our garden is exceptional, a real transformation, and will be enjoyed by our residents for many years to come.
“We’d also like to thank Kirkless Council for their support and funding, everyone who supported the NCS group’s fundraising and the businesses who donated supplies.
“The garden looks amazing and the residents are thoroughly enjoying sitting outside, making the most of the summer weather.”
Nina Baker, Huddersfield Giants Community Trust NCS programme coordinator, said: “What a transformation! I cannot explain how proud we all are of what this team has achieved in four short action-packed weeks.
“They worked so hard to secure donations, funding from the Dragons Den experience and did a phenomenal job haggling down the price of AstroTurf to ensure that Thornhill Care Home wouldn’t go without.
“I can only thank Thornhill Care Home, particularly Marcia, Liz and Johnny for the continued support throughout this whole process.
“NCS powered by Huddersfield Giants Community Trust relies so much on organisations such as Hill Care to take precious time out of their busy schedules to help facilitate a group of our young people and they were absolutely brilliant from start to finish.
“They allowed our young people to break the age barrier stereo type and see what a difference they can make in their own communities.”