Church ordered Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible online and was surprised when a 512-page tome arrived.

The Starke Ayres team says most pensioners want to grow cannabis for medicinal reasons. "They are very particular that everything must be organic and not toxic," says Morris.

A study recently found that medical cannabis was much safer for treating chronic pain than opioids - and most participants reported a dramatic improvement in their quality of life from "bad or very bad" to "good or very good" in six months.

Morris says the centre got 17,000 hits on its site in one week when he put up a post on how to make CBD oil at home.

Walking into Starke Ayres, the Enormous Bud display with potting kits is straight ahead and, on average, they have been selling six to eight a day since they went up in November.

Assistant manager Di Ziman says the surge of interest in "growing this topical plant" has opened up a dialogue between customers about cannabis. "Before it was always hush, hush."