The Duke and Duchess of Cambridge showed off their green-fingered skills and tennis prowess at events celebrating the value of parks and sport.

William and Kate helped nursery school children scatter plant seeds that will attract butterflies and bees during a visit to the 125-year-old Starbank Park in Edinburgh.

They also met teenagers working towards their Duke of Edinburgh’s bronze award and joined them as they planted sunflowers and an apple tree.

After the duchess changed into more sporty clothing, they then took part with children in a youth tennis session run by the Lawn Tennis Association (LTA), which Kate supports as patron.

In the park, the children from Edzell Nursery dropped the seeds on a nature trail which has stations teaching them about classic fairy tales including Hans Christian Andersen’s story The Princess And The Pea.

“You’re very good gardeners,” William told the children as they showed him how to plant the seeds, adding: “We’re going to get a lot of plants. It’s going to be a massive forest.”

The duke recently revealed the duchess is encouraging his interest in gardening so he can share the Prince of Wales’s passion for plants.

During a visit to see community projects in Rhyl, north Wales, he said Kate was buying him a horticultural book by BBC gardener Monty Don: “My wife does all the gardening. I really like it but I have no idea what I’m doing.”

In Edinburgh, he and Kate talked to volunteers who in the last seven years have helped transform the park from a down-at-heel and forgotten space into a much-loved tranquil location used by many in the neighbourhood.

They got down on their hands and knees to help three pupils from Trinity Academy – Ava McKie, 15, Cara Burnett, 14, and Holly Blair, 14 – plant sunflowers as part of the Duke of Edinburgh’s Award.

William, who also planted an apple tree, was happy to give them a hand in the name of his late grandfather, telling the teenagers: “You’ve got free labour, free help.”

The duke and duchess chatted to families who use the park, including new parents Natalie Randamy, 31, and Rory Stewart, 29, and their nine-month-old daughter Penelope.

Kate cooed at the baby as she and William reminisced with the couple about their own children at the same stage.

Ms Randamy said: “We were just talking about Penny sleeping through. They were reminiscing about nine months being a bit of a game-changer for them. Kate was saying Charlotte has the same dress from Next as Penny but just in a bigger size.”

Starbank Park is run by the City of Edinburgh Council and protected by Fields in Trust, which has William as its president – a role previously held by his grandfather the Duke of Edinburgh.

During the event William and Kate launched a new initiative, Fields in Trust’s Green Space Index, which is designed to measure access to parks and green spaces for people across Britain.

Around 2.8 million people live more than a 10-minute walk from their nearest park and they tend to be in the poorest neighbourhoods, but the trust hopes to get more parks designated and protected as only 6% of parks and green spaces are protected in perpetuity.

Edinburgh Lord Provost Frank Ross committed during the event that the city would protect in perpetuity 25 green spaces in addition to 34 that already have that status.

William and Kate later joined a class from Canal View Primary School at the Craiglockhart Tennis Centre for a set of exercises from the LTA Youth programme including hopscotch, floor tennis and team cones.

LTA Youth is a new and inclusive junior programme for children aged four-18 created to help make tennis accessible to as many youngsters as possible.

When they arrived, William asked Olly Scadgell, participation director at LTA: “How are you bringing on a new Andy or Jamie Murray?”

Kate, wearing a Ralph Lauren cable knit cricket sweater, said: “The thing is with children is to give them confidence. You don’t need a fantastic tennis court and greatest kit, it’s about making tennis accessible to all kids.”

During the session, William and Kate showed their competitive natures when they played on opposing teams in a short form of doubles – with the duke coming out on top.

Speaking to the children afterwards, the duchess said: “Thanks for showing us all of your skills. We will have to practice for next time. Some of those shots were pretty hard.”