Recently, Ashley has also been working with Scotsdales Garden Centre in Cambridge, the city where he has been based since he joined Fisons from Quaker Oats more than 35 years ago. "That's been a lot more fun. Seeing how retail works and how the money is made."
Ashley will continue his part-time role marketing Scotsdales, and hopes to develop the application for a new centre at Soham. "That's been delayed - who knows what will happen with planners - but we have a lot of development plans for the Cambridge site and we've also got Fordham, and we could develop that if things go awry at Soham."
Fordham is a nursery and garden centre in Ely bought from EFG by Scotsdales managing director Caroline Owen's father, David Rayner, which now turns over £1.5m a year. Owen says: "John's great. He has tremendous energy and enthusiasm. It's great to have his knowledge. John makes things happen."
Ashley has been making things happen in horticulture since joining Fisons in 1972, when the chemical and fertiliser company was part of the Agrichem business in Cambridge.
"Things have changed dramatically since then," he says. "There were very few garden centres, let alone DIY stores, with most products for the gardener going through corn-seed merchants and pet and hardware shops. It's a very different business now. The range of products has developed. There used to be just one-product companies like Phostrogen, run by Bobby Manners."
The one-man bands have been absorbed and even bigger companies such as Fisons, PBI and ICI have become parts of other companies. "There have been dramatic changes in retailing and product ranges," says Ashley.
Ashley says his biggest achievement is to launch the Miracle-Gro brand in the UK after being asked to do so by its founder Horace Hagedorn in 1988. "That was no doubt the most pleasurable and successful part. It became the biggest brand name in the business in a relatively short time."
Ashley's next big challenge was dealing with the peat debate, when pressure groups decided to focus on the environmental damage caused by digging the product in the late 1990s.
He took a role looking after environmental issues in Europe and the US, and developed his commercial director role in more recent years.
Ashley says: "Friends of the Earth got a topic and inflated it. It was an issue that needed handling that was driven by Brussels and Sites of Special Scientific Interest issues. It's been handled pretty well by the industry working with NGOs such as the RSPB. We've come to a common-sense approach to it. As long as we can produce a good product for amateur gardeners I'm happy."
The new Growing Media Initiative, of which Scotts is a member, is coordinating the industry response to reducing peat use - but is yet to tackle peat use by professional growers.
"The professional side is the bigger problem because the consumer demands the perfectly shaped tomato, for instance, and that is a more difficult task without peat. But something will come out of the R&D box," says Ashley.
On the proposed EU cuts in active ingredients in crop protection - which is set to hit most of Scotts' consumer products including top-sellers such as Roundup - Ashley has bigger concerns. "But it's a big worry for everybody. Part of a recent tour with garden centre owners to the US was to go round Scotts' R&D facilities and see what is coming through. We've got a number of very interesting non-chemical products that don't need clearance so could be on the market very quickly."
Ashley won't say more, for commercial confidentiality reasons, but Owen, who was on the US trip, says: "This research gives us tremendous confidence in the market."
Scotts will "do fine" even if harsh cuts come in from Brussels, says Ashley. "The company is very big, with a turnover of over $3bn (£2bn). But this has been a bad year. We've been hit by price increases and the market is not growing. There has to be some realism in price."
He says grow bags are cheaper now than they were when he helped launch them for Fisons in 1976 at £3.15. Levington compost was £7 a bag in 1972 when he started at Fisons and is now three for £12. "It's been very much a commodity market and only recently have retailers made more out of value-added products." He says the US market sold compost at $1 (67p) a bag, so Scotts told retailers they would make more with a high-specification product. This made more money for everyone.
Ashley adds that his legacy, Miracle-Gro, "has been a phenomenal success" and few would disagree. He only worked 50 days for Scotts in 2008 but general manager Martin Breddy says Ashley will be much missed: "He was the torch bearer for Scotts Miracle-Gro."
1972-2008: Works at Scotts, ending up as commercial director
1976: Launches Fisons grow bag
1989: Launches Miracle-Gro
2000s: Goes part-time at Scotts
2000s: Becomes adviser to Scotsdales Garden Centre