Employers will have to swallow a 3.8 per cent rise to £5.73 an hour (from £5.52), after rising food and energy bills put pressure on household finances. For 18- to 21-year-olds the rate will be £4.77 (from £4.60), while 16- to 17-year-olds will get £3.53 (from £3.40).
When introduced in 1999, the rate was £3.60 an hour. It last increased in October 2007.
The Government plans to crack down on employers not paying the right level, with those caught now facing an unlimited fine.
Union leaders have welcomed the move but want it to go higher, with one calling for a more realistic figure of £6.75 an hour.
But Garden Industry Manufacturers' Association director Neil Gow said: "It adds to the operating costs of business significantly. It removes the opportunity and flexibility that employers have to reward good people who do good work."
"It probably affects retailers more but if it's driving up retail costs, they're going to be looking for recoup that by buying product cheaper which is not good for suppliers."