This season's sales growth area in the horticulture industry is definitely "grow your own". But how can growers and garden centres make the phenomenon last?
After all, in the 1970s, when TV show The Good Life, together with the drought and oil price hikes, led to vegetable seed sales exceeding the sale of flower seeds, the craze died down within a couple of seasons.
This time around, Jamie Oliver is gaining the credit after his Jamie at Home series was repeated at a time when gardeners were keen to buy seeds - when C4 first broadcast it in 2007 it was too late in the season. The Jamie effect follows on from 2007's BBC series Grow Your Own Veg, fronted by Carol Klein, which spawned one of the best-selling non-fiction books of the year and prompted a slew of copycat, cash-in tomes from publishers.
Last week, national newspapers picked up on the trend from HW, ahead of the Easter boom.
Mr Fothergill's has seen edible-seed sales top ornamentals by four to one. Vegetable seed transactions now account for nearly three-quarters of Unwins' business, up from about one-third five years ago. Westland has recorded an increase in vegetable seed sales of up to 40 per cent in a year.
So, what next? Boom and bust like the 1970s, or a sustained increase in interest in "grow your own"?
Garden writer Peter Seabrook says manufacturers and garden centres must give newcomers advice. Knowledge is undoubtedly poor. One national newspaper writer's garden editor told him to remove the word "chit" from a piece on potatoes because no one knew what it meant. "Now is the time to sprout your seed potatoes" was what appeared in print.
Seabrook says: "If we're not careful the bubble will burst very quickly as it did in the mid-1970s. At the time of the drought there was a great revival in 'grow your own', and vegetable seed sales outstripped flower seeds, but people soon found it was not quite as easy as they were led to believe.
"If we're not careful this time, it could go exactly the same way. There is some work and effort in growing your own. We need to be explaining that more."
Meanwhile, retailers are revelling in the upswing. Derek Bunker, owner of Alton Garden Centre in Wickford, Essex, says the influence of local hero Oliver has driven the demand.
"Jamie's from just down the road, and I'm a great fan of his. He's a down-to-earth guy. It's because of his 'grow your own' thing that we've sold twice as many seed potatoes this year as last year. Luckily, a double load was delivered to us by accident. We said we'd keep them and see how they went and we've sold them all. There has been a shortage of some varieties this year because growers have only grown a certain amount."
He adds: "Thirty-odd years ago some garden centres sold half a hundred-weight [about 25kg] but we didn't sell many because back gardens are small in Essex. But this year we've sold a lot of potato barrels, which are good for patios and small spaces. Last year we only sold 20 but this year it could be five times as many. It's the novelty of 'grow your own', not because potatoes are any more expensive in the shops.
"The 'grow your own' classic for this is tomatoes. We sell three tomato plants for 50p each, then a grow bag for a couple of quid, then a bottle of tomato food for £3.99 and some canes. So the three plants becomes a spend of £10-15 and then there's a glut of tomatoes in the shops and they're 10p a pound. But gardeners have got their own tomatoes and they taste so much better. It's not because prices are going through the roof," Bunker explains.
Westland marketing director Keith Nicholson says: "Demand is growing year-on-year on seed potatoes. We'll need more acreage planted next year. And we just can't keep up with demand for our new vegetable-growing compost."
Garden & Leisure sundries buyer Mike Cook explains: "On the back of the 'grow your own' phenomenon, seed potato sales are 40 per cent up on last year. Large bags are the biggest sellers, which is leading to a shortage."
Thompson & Morgan e-commerce manager Clare Dixey says: "We have seen a big rise in seed potato sales compared to last year. We're at least 10 per cent up. It's all down to 'grow your own' fever. Everyone wants to have a go. More and more people are taking out allotments and Jamie Oliver's programme must be having an effect.
"And the economy is tightening," Dixey points out. "People tend to buy more seeds and crops to save money. Last summer there were reports that fresh produce prices would rise so people want to grow their own rather than face price rises in supermarkets."
Suttons vegetable products buyer David Marland says sales for seed potatoes this season are up 20 per cent on the same time last season: "Seed potatoes are doing very well at the moment. The whole vegetable side of the business has been going up. People are really going for 'grow your own'. Any influence from the TV and people like Jamie Oliver are definitely having an effect. Last year when Carol Klein planted Jerusalem artichokes on her programme, sales went from 150 plants in a year to more than 1,000 in three weeks, so putting it on TV definitely has an effect."
Seabrook adds: "It is not just the Jamie Oliver effect. At least seven of the manufacturers are offering containers to grow potatoes this year - this is as a result of the demand begun last year."
The British Potato Council's Potatoes for Schools campaign must be having an effect, too. Last year, 2,000 schools grew potatoes because of it. This year it's 10,000. And the Five A Day, sustainability and health kick ideas are all coming together to have an effect.
"But we need to be aware that flower plug sales are growing. People grow more flower seedlings than seeds now, so the market we should look at is seeds and seedlings together for both flowers and vegetables," Seabrook explains.
20 per cent increase in sales of seed potatoes in the past year
30 per cent increase in vegetable seed sales in the past five years
14 per cent increase of seeds and bulb sales in February
£62m taken for seeds sold in 2007
Sources: GCA and HTA