The popularity of a vegan diet has spread to the vegetable patch with gardeners demanding animal-free fertiliser and compost.Suppliers are being asked to guarantee their fertilisers are plant based are manure pellets come from free-range animals. The Royal Horticultural Society has said that if the trend continues, stockists will have to look at producing vegan options to meet demand.Guy Barter, Chief Horticulturist at the Royal Horticultural Society, explained: “Vegan gardening is similar to organic in that it avoids synthetic pesticides and fertilisers but goes further; eliminating anything of animal origin which includes popular feeds with animal materials such as fish, bones and blood and manures from intensive animal farming.–– ADVERTISEMENT ––”Ornamental plants need only a little feeding, fruit and veg a little more, but seaweed fertiliser, green manures and home composts, generally speaking, more than suffice. “Vegan gardening is a rising trend because we now know so much more about what we eat thanks to the internet, and there are some fantastic role models on Instagram and YouTube.“Vegan gardening products are more limited when it comes to important bulky soil improvers like manure. For instance, most suppliers of chicken manure pellets can’t even offer a guarantee they come from free range chickens, because they don’t, so I refuse to use them.”I don’t have a problem with manures being used to improve soil because in the wild plants are smothered in poo all the time. But where and how that is sourced for gardeners is important. I’m sure most people care about the environment and animal rights, if more options were available they’d fly off the shelves.”The number of vegans in Britain rose by more than 360 per cent to some 542,000 people in 2016, according to a poll of almost 10,000 people carried out by Ipsos MORI for the Vegan Society and Vegan Life magazine.The Vegan Society said at the time that the survey proves that veganism is now one of Britain’s “fastest growing lifestyle movements”. Charles Dowding, a pioneer of organic growing, wrote in Gardener’s World Magazine: “I am in agreement about not using manure from battery farms, or bagged chicken manure from the same intensively-farmed source. However, I am also happy to use manure from local equine stables, free-ranging beef cattle and home-raised hens.” “Should we see more in the coming years, the industry will need to look at providing more products, such as alfalfa meal fertiliser, currently a niche product, that meet this growing demand.”Landscape designer and allotmenteer Jack Wallington has been dabbling in vegan gardening in an effort to be more environmentally-conscious.He told The Telegraph: “Using homemade compost and fertilisers made from nettles and comfrey, plus shop bought seaweed fertiliser means my allotment is largely vegan already. Vegan gardening is a rising trend because we now know so much more about what we eat thanks to the internet Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.