Britons spend an average of £30,000 on their gardens over a lifetime

How much money does a garden deserve to have spent on it? That's the big question we're mulling over this weekend, putting our feet up and contemplating the bare patches, the unrepaired fence panel and the almost physically untrimmable tree, which gives me arm ache just looking at it.

A recent survey commissioned by GardeningExpress.co.uk found that British gardeners will spend an average of £30,000 on their gardens over their lifetimes. I'm left with an immediate, urgent set of questions. In particular, I want to know which bits of the garden they're all spending it on. For example, it's no surprise to learn after scrutinising the study's findings a bit more deeply that a cool £10,000 of that £30,000 goes on plants "often fuelled by impulse buys on garden centre visits". A deep aargh of recognition.

Hard landscaping makes up another massive chunk of our lifetime horticultural splurge: £9,000 on average will be spent, as homeowners renew patios and decking an average of SIX TIMES during their adult years. Wait a minute. Seriously? SIX? Crikey! How do they have the energy?

Plus, after the massive cost of house-buying, who really longs to chuck in another £4,000 for the garden to be redone? At the end of kitchen fitting and other modern pleasures, the logical move would surely be a nice holiday away from all those still-not-unpacked- moving-boxes. Not a patio.

I am so puzzled by some of the survey findings that I start a quick rival survey in the playground. My friend Leanne, pushing her daughter on the swings, explains her strategy.

"So this week I bought a Scratchcard: the first number I scratched off was £2,000, so I said, well with that I could buy all the bamboo I want for the end of the garden, and plant the Ann-Marie borders." ("Ann-Marie borders" has become shorthand in our road for ordering from Crocus.com all of the plants that are featured in the most seductive border in Ann-Marie Powell's fabulous Plans for Small Gardens published by Pavilion, £16.99.)

Though as Leanne continues: "But if I got £250,000, then I could just get actual Ann-Marie."

Daydreaming aside, very few people ever spend £30,000 in one go on their garden – although if they got a loft extension for that price they would consider it a huge bargain, and it's easily possible they might use it for fewer hours a day than a well-designed outdoor area directly connected to the kitchen.

Joe Swift, TV gardener and owner of design company Modular, feels passionately that British people need to learn to spend more on their gardens, not less. "You should consider your garden to be part of the value of your house," he urges. "When you think of it that way, it's a lot easier to justify the spend."

But how much is enough? So far this year I've spent about a hundred quid, though that doesn't count the £30 I finally shelled out to the council for collection of green waste. And often the expense doesn't quite seem commensurate with the results: last summer I splurged on some spectacular tulip bulbs, "Avignon", flowering right now with enormous tigerish cups of red streaked with orange and yellow; unfortunately only I can see them, out of the front window, because I planted them in such a stupid place.

And finally, of course, there is the whole question of my "lifetime" spend. What if I want to be buried in my garden? This leads to the intriguing possibility: could I spend on my garden even after death? I'd like to think it was a fitting tribute to the way I carry on during my waking hours if I were to continue shelling out on unnecessary garden expenses from beyond the grave.

And when I look it up online, it turns out that by an 1880 law, in most places it's easier to be buried in the garden than to start work on that useful garden office. And frankly, at the rate I carry on, much more likely to happen.