Developers and landlords should give tenants a “right to garden”, a leading horticulturist has said as he campaigns for more green spaces in new-build homes.

To inspire those who live in homes without gardens, Jason Williams worked with students to create balcony gardens for the Royal Horticultural Society urban show, held this month in Manchester, to demonstrate what can be done in a small space. Each garden cost £500 to create. He also created an example allotment with easy-to-tend plants, which a developer could easily put into a new-build block of flats.

Williams, who calls himself the cloud gardener, has become known for the lush plants he grew on the balcony of his Manchester flat. Unusually for a horticulturist who displays his work at flower shows, he does not have a garden of his own.

Williams is campaigning for developers and landlords to create spaces for tenants and leaseholders to grow plants, and says it should be part of their responsibility to give green space to the people who live in their developments.

“People are crying out for green space, especially now with this cost of living crisis,” he said. “Things are getting so, so difficult for so many people across our towns and cities and green spaces are a really, really great way of helping people with their wellbeing. And I think that if we can just encourage developers just to take that next step, I think that will really, really be impactful.”

Williams said he thought tenants should have a right to garden, and said he had seen examples of renters being banned from gardening.

“It’s really interesting because especially as a renter, you become even more powerless. People have reached out to me and said, actually, I started balcony gardening or I put some pots out around my terraced home. But the developer then said no, you can’t have those pots there because there’s a fire risk. And then all of a sudden, you get completely shut down,” Williams said.

Other tenants have also blocked people from gardening, he said. “I’ve had it where somebody said that they put out a nice seating area in their communal space, but actually, another resident complained to the building manager that they didn’t want people loitering because they could then look up into their apartment. And so what the building manager would do is, rather than having to try and negotiate that, is just flat out say no, take it down.”

New laws mean developers who create new builds have to create “biodiversity net gain”, which means having at least 10% more space for nature on the plot of land than there was before they built it.

But these areas, Williams said, are often not gardens and do not give a huge wellbeing benefit to the people who live in the developments: “So if they had taken over a car park, and they put some shrubs in it, well, now it’s 10% better so they think: why do I have to do any better?

“We hear things like, let’s get some seeds and then put them out on your windowsill. When you live in a city, in one of these developments, we have floor to ceiling windows. For us, there’s no such thing as a windowsill. So there needs to be some form of a cultural reset here to not negate what’s already out there, but also include other people.”

Williams says it is easier for developers to get planning permission if they create beautiful communal outdoor areas: “What developers tend to do is they will make the space that they want to make and everybody else has to deal with that. So for me, what I will be doing is going out and finding out what it is that community wants from that space. Because if you’re being told that you’re going to have a 50-storey building just magically appear next to you, and you’re not even getting anything from it except for more traffic, more pollution, higher strain on your local amenities … if you as a developer were to say listen, we’re going to create these wonderful pockets where you can … have access to community gardens, that is a much softer pill to take.”