The life I loved came to an abrupt end when I was diagnosed with severe myalgic encephalomyelitis (ME), also known as chronic fatigue syndrome, in 1997. For years, my world revolved around bedpans, bed baths, wheelchairs and stairlifts. Then an unexpected gift began to revive a sense of joy I thought I had lost for ever.

I grew up in a gardening-mad household. As a child, I would help my dad tend his prize roses, rake the lawn and carry home the weird-looking leeks and cauliflowers he grew on his allotment. He was my hero and I was never far from his side until he died when I was just 11. From that moment on, gardening lost its appeal: the memories were just too painful. I turned my back on all things green.

In my 20s and 30s, I opted for a career in the city – working in London and Manchester as a marketing consultant for brands including Pepsi and Sony. The closest link I had to anything green was the vase of dead flowers on my desk.

Then, at 32, a year after my diagnosis, I collapsed in a Sainsbury’s car park. I had to be carried to the car by my husband, Andrew, and then up to our bed. Neither of us realised it would be five years before I would be physically strong enough to walk back down the stairs on my own. I had been struck down by the most severe form of ME – a physically disabling illness for which there is no cure.

Before I became ill, I used to think ME was just about being tired. How blissfully ignorant I was. For the best part of two years, I was little more than a breathing corpse. All I could do was lie in a blacked-out room in constant pain, unable to talk, walk, sit or stand. I had to be spoon-fed, watered, washed, dressed and nursed by my family. My career was over. Those wonderful memories of being outside with my beloved dad remained buried deep.

After two years, the severe light sensitivity passed, but I would be virtually bedbound for another three years. During that time, however, I began to take baby steps. Literally. I started to walk from my bed to the toilet unaided. I started to feed myself. I started to sit in a chair for 10 minutes a day. I started to put on my own socks.

But after five years of this hell – including hospital admissions interspersed with terrible relapses – I was broken. Physically, mentally, emotionally. The toll this cruel illness had taken on me was enormous. I was a shadow of my feisty, confident and fun-loving self. Now, I was permanently anxious, nervous and disheartened – some days, I just wanted to go to sleep for ever so I could join my dad and feel safe again. I thought about suicide, but something inside stopped me.

Then, one day, my dear mum brought me my breakfast. On the tray was a tiny, beautiful potted plant, topped with dense heads of small, coral-pink flowers. “Something for you to look after,” she explained. Looking at her in disbelief, I thought: “I can’t even shower myself – how the hell am I supposed to look after that?”

But on my windowsill it sat. And you know what? That little plant changed everything. Helpless as a baby, just as I had been, it needed me. For everything. So, when I woke up each day, it was the first thing I would check on. Did it need water? Did its leaves need to be wiped? Did it need to be fed? Did it need more sun? More shade? That little plant gave me purpose. Watching it grow – its little buds forming, its flowers bursting into life – gave me a sense of joy I thought I had lost permanently.

That plant, a kalanchoe, thrived. It made me realise that, in order to heal, I had to get outside. I had to start gardening. I had to return to my past to move forward. I had to get my hands in the soil, smell the grass and touch the trees. I needed that connection to nature, which I had taken for granted as a child and lost as an adult. My body needed it. My mind needed it. If ever I were to find peace, I needed it.

So, getting out into the garden became my goal. It took another year for me to be strong enough to attempt it – and involved the installation of a stairlift – but get outside I did.

And it was magical. I can still remember sitting outside in my wheelchair and feeling the sun on my face again for the first time. I felt hope: that I could get better, that this life of severe disability would not be the end of my story. And I felt my dad with me. Strongly.

Starting out, all I could manage was five minutes a week. But I worked my way up to five minutes a day, then 10, then 20 and upwards. Some days, the gardening activity was to sit in a chair for half an hour, watch the bees, listen to the sounds and enjoy the scent of my flowers, but that was OK.

Over the next 10 years, gardening helped me rebuild my life. As my plants grew stronger, so did I. As my garden grew bigger, so did my world. My illness had robbed me of my health, confidence and joy. Getting back to my roots – to gardening and growing food again – gave them back to me. I give thanks every day for the tiny, beautiful potted plant that led me back to gardening – and back to life.

Grow Your Own Food Lady Muck Style by Catherine Saunders is out now (Timga Publishing, £10.99)

• In the UK and Ireland, Samaritans can be contacted on freephone 116 123, or email jo@samaritans.org or jo@samaritans.ie. In the US, you can call or text the National Suicide Prevention Lifeline on 988, chat on 988lifeline.org, or text HOME to 741741 to connect with a crisis counselor. In Australia, the crisis support service Lifeline is 13 11 14. Other international helplines can be found at befrienders.org