Vitamin D is produced in the body when the sun's UV rays contact your skin, and helps your body absorb calcium.
The Ministry of Health recommends getting vitamin D by being outside for even a few minutes but also warns to use appropriate sun protection to avoid sunburn.
"But then there's also the side of it where you plant something and then watch it grow and see the wonder of nature. You don't actually make it grow, it grows itself," Carter said.
Carter had his first gardening plot when he was 6 and was taught how to garden by his parents, and said his grandma had a story for every tree in her garden.
"Positive memories are often associated with gardening."
Carter said, at the garden centre, customers would also share stories associated with the plants they saw in the shop.
"Regulars come into the garden centre maybe every second or third day, they may or may not buy something, but they share stories and call the centre their happy place.
"People just have a feeling they get from being around things that are living, growing and flowering."
This is also called the 'biophilia hypothesis', which is the idea that humans possess an innate tendency to seek connections with nature and other forms of life.
Carter said interacting with plants in your garden also provided a sense of safety within a busy world.
"We've hit the shortest day, the weather's bad, people are getting Covid, but plants just keep growing. That tree outside your window will continue to grow," he said.
"It gives you a sense of satisfaction and relaxation because it's different to dealing with people, and removes you from the business of things."
Clinical Psychologist Dougal Sutherland said the sense of achievement in gardening was very tangible as you can see the plants as they grew.
"When we engage in activities we are successful at we feel better about ourselves and it's great for our wellbeing. We feel like we achieved something."
Sutherland said one of the ways to feel a sense of achievement while gardening was while in the "flow state".
The 'flow state', or being 'in the zone, is described as the mental state in which a person performing some activity is fully immersed in a feeling of energised focus, full involvement, and enjoyment in the process of the activity.
Sutherland said in order to achieve this, you had to be good at the activity but still feel challenged by it.
"It won't be every time you're in the garden but when you're planning, moving things around, thinking about your garden, there's probably that element of being challenged."
"Mowing the lawns and doing a little bit of weeding probably won't get you into the flow state."
But he did say these more "mundane" activities could lead to problem-solving and good ideas.
"People experience this not because they're focusing on mowing the lawn but because they're able to free up some mental space for that to tick away in the background."
He likened it to having many apps open on a phone.
"When you close them all down and just have one open, there's a whole lot of background noise that disappears," Sutherland said.
"Assuming you're gardening because you enjoy it, this can result in increased pleasure, relaxation and improvement in mood which in turn can relieve anxiety and other negative feelings."
Sutherland said the positive endorphins from doing something enjoyable on top of the positive endorphins from the physical exercise while gardening often led to increased mental wellbeing.
Carlos Rippon is one of the lead volunteers at Matipo Community Development Charitable Trust which also runs a community garden on Matipo St in Castlecliff.
The trust runs horticulture courses and grow vegetables in the community garden which people from the area can participate in and come help themselves to once grown.
He said seeing people grow their own food for the first time had a significance you had to see to explain.
"They've grown it themselves and their family is eating it. Especially for the younger ones that have never done anything like that. It's an achievement and they're doing something that feels meaningful to them."
"They get some free healthy food and set an example for others instead of being out on the streets drinking and whatnot," he said.
Rippon's dad Craig Rippon started the trust in 2015 to provide education and eventually some employment for young people, and the trust won the supreme Trustpower Award in 2019 for its work in the community.
When Craig died Carlos stepped up.
He said his dad saw something in the future of employment in riparian planting for New Zealand and wanted to help provide those opportunities for the community.
"A whole lot of New Zealand has got to be planted. Every waterway in New Zealand has got to be planted with riparian planting to provide habitats for animals and stops slips," Carlos Rippon said.
He said the community centre students were educated so they're fully qualified through Land Based Training Ltd which provides the educational side and the courses.
"So they get qualifications and they get to learn how to grow their own food."
He said there was lots of interest in taking part in both the community garden and courses.
Five students had just finished a level four sustainability course, 19 are signed up for a level 3 carpentry course and they've had a handful of graduates.
Longtime Whanganui Gardening Club member Megan Grant said over time more people had become interested in gardening.
"We have monthly meetings, and it used to be all elderly people," Grant said.
"Now there are more people, and many more younger people."
She said gardening offered a chance to constantly learn and exchange knowledge, which was an important aspect of feeling connected to the community.
"I learn something new every day from gardening."
Grant owned an edible flowers and microgreens business for five years in Ratana and said growing microgreens provided "instant gratification" because of how fast they grew - which in gardening time meant between seven to 10 days.
As for the flowers, Grant said the colours and smell were stimulating for her mind.
"You've got the beautiful smells, your hands in the soil, and quietness.
"It's calming. You can go out and do it by yourself whenever you want."
WHERE TO GET HELP
If it is an emergency and you or someone else is at risk, call 111.
Safe to talk (sexual harm): Call 0800 044 334 or text 4334
All services are free and available 24/7 unless otherwise specified.
For more information and support, talk to your local doctor, hauora, community mental health team, or counselling service. The Mental Health Foundation has more helplines and service contacts on its website.