Since March, attendees at the charity have been helping the castle keepers to move tonnes of soil and tend the borders.
Grow supervisor Andrew Chandler said the medieval surroundings had provided an enjoyable environment in which to work, particularly towards the end of the island’s second lockdown.
‘It’s been great,’ he said.
‘We’ve had our own space, which has been lovely. We’re looking after the borders around the castle – on the lower reaches – and the top lawn as well.’
Mr Chandler said the castle’s location determined what could be grown where.
‘You’re really exposed to the wind and the elements,’ he said, ‘and it depends from one side to the other what you can grow, but much of it is sun-loving plants and plants that won’t need too much water.
‘If you’re overlooking Havelet Bay, it’s a hotbed up there.’
Head of Heritage Services Helen Glencross said the charity had been invited to work at the castle after working successfully on a similar project at the Guernsey Museum and Art Gallery at Candie.
‘We’re absolutely delighted to work in partnership with Grow Ltd,’ she said.
‘They’ve done a fantastic job helping us to prepare for the season.’
Grow team member Benjamin Tardif said working at the castle could be a little stressful when it was busy, but when it is less crowded, it was very peaceful.
‘We keep focused on putting the plants where they need to be put and make sure they’re looking healthy,’ he said.
Fellow attendee Heather Brown said: ‘It’s different to what we normally do at Grow Ltd. ‘It’s really interesting and you get to see lots of different wildlife.’
Kieran Trebert, who is also on the Grow team at the castle, identified another good reason to enjoy the work.
‘It’s nice to come here without having to pay, for once, but I also get to see what goes on behind without several people here.’
n Castle Cornet opened its doors for the new season on Friday and will open every day from 10am to 4pm until 31 October.