It all started with a box set of Roots we had picked up at a car-boot sale. I watched the first episode with my son and he seemed quite taken with the part where the young Kunta Kinte goes off into the forest with a dozen other adolescent boys for "manhood training" – specific tests of strength, bravery and hunting skills – culminating in an eye-watering circumcision with a two-pronged knife.

Why not set him a 21st-century, western (pain-free) equivalent, I thought. Fred was just a few weeks away from his 13th birthday, which seemed like an important turning point. He was eager for more freedom and independence, pushing to go to bed later, have more pocket money, not have a babysitter, cycle to random far-off places and go to football matches without an adult. But did he have the maturity and worldiness to be granted these things? Let's put him to the test, I thought. Now seemed the perfect time to make sure he had the skills needed for a more grown-up life.

However to get him fully on board, I knew I would have to invent a rite of passage that would appeal to a modern 13-year-old who already had his boxers permanently on show.

After all, this was a boy who hated sustained effort and shied away from any kind of system or daily ritual: he spent no more than three minutes on any homework assignment, washed pans so quickly that the before and after effect was negligible and had still never read a book on his own. I had even resorted to putting a picture of a mouthful of rotting teeth above the basin in the bathroom to persuade him to use his toothbrush.

On the plus side, he was cheerful, articulate, funny, interested in the world far beyond his own small universe, physically adventurous and naturally outdoorsy (a friend had recently texted to say she had just seen him floating down the river on a hollowed-out log). I wanted to set challenges that played to these strengths, but also targeted his weaknesses.

To engage and motivate him, I decided to put a sort of life-as-a-game spin on the whole thing. There would be 13 challenges covering 13 different areas of life, and each challenge would arbitrarily contain the number 13 in some way if possible. I even bought 13 brightly coloured envelopes in which to present the tasks to him, one by one.

Challenge one: Get on a train on your own. Get off at the 13th stop. Go to a sit-down cafe or restaurant. Order the 13th item on the menu. Then buy yourself a whole outfit with £13.13.

Fred is instantly upbeat about this one. "This could lead to me being a millionnaire, Mum," he says. "Richard Branson's mum drove him to the countryside and left him there to find his own way home."

I am not, of course, randomly releasing him into the wild. I have secretly micromanaged the whole thing. We are going to put him on a train at a particular rural station and after two hours he will end up in Hereford – a city he has never visited. I buy him a ticket and order him not to look at the destination. I am feeling quite uneasy, but as the train pulls away, I smile and think of Kunta Kinte's mother's words when her son is taken from the village: "A boy has just left, a man will return."

Fred does not know, but we are driving to Hereford to collect him. When we eventually meet up, he tells us he loved the solo train journey and the shopping, but was very uncomfortable with the lunch element at first. "It's a bit weird, isn't it? A kid on his own sitting in a cafe?"

I am less impressed with the outfit he has bought. It includes white canvas shoes (white, for goodness sake) and a T-shirt with the words "I was amazing last night. Ask your girlfriend" on it.

Challenge two makes him groan: 13 household tasks, from ironing to paying a bill to defrosting the freezer. "Blimey, that'll take me all day," he says, looking at the list.

Nevertheless he starts off enthusiastically with the first job of mowing the lawn, claiming he is going to make football pitch stripes. Minutes later, he pops back into the house to say he has remembered that he needs to hang out the washing. "I'd better do it now 'cause it looks like it might rain later." Brilliant. Thinking like a housewife already.

By the last task – putting up two racks of coat hooks – he is visibly flagging, yet perseveres. He certainly proves that he has a good command of a range of swear words.

Challenge three really hits his weak points: learn, practise and perform a 13-bar blues piece on the piano in public. Fred had a few months of piano lessons, but gave up. His dad has tried to teach him a bit, too, but that never ends well. But he is happy to write down the notes from a YouTube pop video and have a go on his own.

The idea of regular, repetitive practice, however, goes against every bone in his body. We tell him it is going to be much scarier than when he was Joseph in the nativity play or banged the triangle in the school orchestra, but it is a struggle. He even lies some days and tells us he practised while we were out.

It is only when we arrive at the event, an open-mic night with a proper stage and an audience of 60 or 70 that his nerves kick in. He babbles and becomes fidgety. However, he performs well and receives huge applause and cheers. He is high as a kite all the way home.

Three challenges down, 10 to go. I know he is enjoying it when I overhear him telling a friend animatedly about what is inside the next coloured envelope, which I have left on the kitchen table.

The next challenges get him cooking (plan, buy and make from scratch a three-course family dinner, choosing dishes from any page 13 of our recipe books), learning Hungarian (Fred has been invited to Hungary in the summer holidays with his best friend's family), doing a self-portrait to capture himself at age 13, and walking (plan and do a 13-mile walk on your own). I know this distance will not be that strenuous for him. What I really want is for him to experience how liberating and meditative it can be to walk for an extended period of time with nothing but your own thoughts. I tell him he can't take his iPod.

Challenge eight is to volunteer. I have a romantic vision of him dishing out soup in a centre for the homeless or spending time with old people. In reality, health and safety makes this impossible. He ends up in charge of the hook-a-duck stall at a local farm charity for a day.

Afterwards, he is dismissive about the concept of volunteering, but seems fired up by how easy it was to make money. "All I had a was a paddling pool and a few plastic ducks." Perhaps that in itself was a seed worth sowing.

With five challenges left, Fred is asking what his reward is going to be at the end of all this. When Kunta Kinte's initiation ceremony is over, his father puts a tribal leather pouch around his neck as a token of his new status. They look into each other's eyes for a brief moment, full of pride and emotion.

Similarly, I had hoped the sense of achievement Fred felt at completing the challenges would be enough. Silly me. This is a child of a generation used to getting sweets between every layer of pass-the-parcel. Children are given certificates for completing spot-the-teddy treasure hunts, football trophies just for being in the team. "What I'd really like," he tells me, "is if you took me to Blackpool Pleasure Beach." Should I? I'm not sure.

But there have been pay-offs already. He plays the piano a lot these days, cuts the grass and we know we can ask him to make dinner if we are too busy. Now when he goes to stay with his grandparents 100 miles away, instead of a personal handover of child, clothes and cuddly toy at a service station halfway, we put him on a direct train with a heavy rucksack.

I also think he has learned that effort leads to reward, that he can do whatever he puts his mind to, that it is worth feeling the fear and doing it anyway, that we trust him to do stuff he thought we might not, that being in your own company is just fine – and that life is full of possibility and playfulness if you want it to be.

In fact, I may have made a rod for my own back.

"When I'm 18," he said the other day, "Do you think you could you set me some sort of treasure hunt around Europe?"

Keeping the Little Blighters Busy: 50 refreshingly different things to do with your kids before they're 12¾, by Claire Potter, is published by A & C Black, £5.99. To order a copy for £5.99 with free UK p&p, go to theguardian.com/bookshop or call 0330 333 6846