Buy liquid frost cloth to protect your tender plants from frost. This organic spray-on liquid protects subtropicals, veggie seedlings, citrus and any frost-tender plants from biting winter temps and drying winds. It will protect down to -3°C.
How? It's a wax coating that's both protective and non-toxic. Used by commercial organic growers for years, each 200 ml per bottle makes 8ltrs of spray.