If you’ve got a small city garden, balcony or just a windowsill, Carolyn Dunster knows how to make the most out of every inch of space

“It’s that miracle of life, of starting off with something that basically looks like a speck of dust and nothing more and planting it with hope,” says Carolyn Dunster.

“I think it’s really important that as human beings, especially if you live in a city, you have some sense of connection with nature. We are programmed to be connected with nature and if we’re deprived of that, it has a negative impact on us.”

Carolyn is a florist and planting designer, who has felt the importance of flowers from an early age. As a young girl growing up in Devon, she had a patch of the garden to herself, spending her pocket money on seeds and growing what she chose.

“Even when I was a tiny child I used to love going out into my parents garden and picking little posies so I think I’ve always loved having flowers in my life whether or not I’ve grown them or bought them.”

After coming to London, for a number of years she moved around a series of flats without the space to grow plants but has now settled in Islington where she has a front and back garden.

“I’ve just given over every space to growing flowers,” she says. “I had children that wanted grass for a long time, but we’re over the grass thing now, so I dug up the lawn and I put down gravel and grow flowers in the gravel.”

Carolyn’s new book Urban Flowers is an in depth and comprehensive guide to creating your own plot of flora, even with limited space.

“Some people will swear by having raised beds and growing everything in rows and I wouldn’t knock that – but if you’re limited for space, by sewing in gravel you can sew quite randomly. I don’t do everything in straight rows so the gravel tends to act as a bed in itself in terms of helping seeds germinate more quickly than sewing directly onto soil.”

In her book, she helps you work out how to evaluate the space that you’ve got, choose a style that fits, select the right plants for the plot and reap the benefits of what you’ve grown. Accompanied by vibrant pictures from Jason Ingram and Nicholas Hodgson, there are step by step guides to creating hanging herb gardens, advice for how to personalise using recycled materials and guides to which flowers work when – in short everything you need to know.

“I think the biggest mistake that people make is rushing off to the garden centre or the market and just buying something that they fall in love with without doing any research and without working out whether that particular plant is going to be suitable for the location they have in mind - right plant, right place.

“My thing is to not go and spend loads of money, which is why I like to grow my own flowers from seeds because it doesn’t cost a fortune and it gives you a chance to experiment.”

She recommends planting flowers such as Nigella damascena (love-in-a-mist) which is coming up now in her own garden. Sowing “hardy” annuals like this in the autumn means you get a crop of early flowers and sowing again in spring can ensure a succession period.

“With anything ‘half hardy’, you wouldn’t put them in until the ground is warm enough to sit on,” she advises. “That’s the key. If you can sit on the ground and it’s warm enough for you without a blanket, it’s warm enough to start sewing seeds.”

While she is a florist, Carolyn’s dedication to gardening is about more than just her job – she loves the living in London but feels the need for nature. We know already that plants are essential for our physical health, but she says the positive impact on our mental health is just as vital.

“I think we’re all so tainted and cynical about stuff and think we can just go out and buy something and when it breaks you can just replace it immediately with something else. With plants you can’t do that. You have to look after them and nurture them and I think it slows you down, it stops you in your tracks, you really get into the whole rhythm of gardening. It’s very tactile and you have to learn to be patient.

“You may be waiting 6 weeks but when you finally see some tiny little green shoots coming up through the earth, it’s just amazing.”

Urban Flowers: Creating abundance in a small city garden (Francis Lincoln, £20) is out now.

Carolyn is exhibiting at the Royal Horticultural Society Summer Urban Garden Show from July 11 to 13 at the RHS Lawrence Hall.

Five tips for an urban jungle:

Plan before you plant

Measure the space carefully and draw up a plan on paper before committing anything to soil. This will help you decide how to make the best use of your space. But don’t forget that trial and error will always be a factor, so don’t worry about the odd mistake.

Do your research

Some plants will work in some places and others won’t, so make sure you know before you purchase anything whether it suits the spot, has enough sunlight or shade and works with the soil.

Use what you’ve got

Walls, stairwells and drainpipes can all be optimised if you have no ground to plant in. There are endless easy ways to suspend your flora – just make sure that potted plants have enough drainage.

Harvest it yourself

Once you’ve got your first cuttings, flower markets will be a thing of the past. Knowing how and when to harvest the seed heads properly is important: too soon and the seeds won’t germinate; too late and nature will have taken its own course.

Guerilla gardening

If you have no outdoor space of your own, work with your community to increase plant life in the area. Plant flowers in pavement tree pits to enhance the street for everyone, and give any abandoned wasteland a makeover.