“Moth orchids are tropical plants…”Shutterstock/SoNelly With such a wholesome image, the world of horticulture can have some surprisingly passionate debates. So while it is probably extremely unwise, I thought I would wade into one of the most heated questions in gardening in recent years: should you really water tropical orchids with ice cubes? Bear with me… I first came across this idea over a decade ago at a horticultural trade fair in the Netherlands, where giant commercial orchid growers were unveiling a glossy new campaign. Oversized retro fridges and fake ice sculptures were festooned with live orchids, under a…