Visitors to Kew's country garden are being asked to drive or walk over disinfectant matting to protect its livestock from foot-and-mouth disease.
Wakehurst Place visitors will face biosecurity measures
The voluntary biosecurity measures have been introduced at Wakehurst Place, West Sussex even though it is outside the protection and surveillance zones.
"Our top priority is the health of Wakehurst's flock of Southdown sheep," said spokesman Iain Parkinson.
A temporary foot-and-mouth zone at Haywards Heath was lifted on Wednesday.
Laboratory results showed the disease was not present.
But West Sussex remains a high risk area for foot-and-mouth, with movement restrictions in place.
Eight farms in Surrey have been found to have the disease since August.
Wakehurst's sheep are used as "nature's lawnmowers" on the garden's meadows and heathland.
Mr Parkinson said they were an integral part of its grassland management.
Since the foot-and-mouth outbreak, the flock has been isolated and electric fencing installed to deter visitors from approaching and petting the animals.
"We check Wakehurst's sheep twice a day and I am very pleased to report that they are in excellent condition," said Mr Parkinson.
"By being proactive and introducing precautionary measures we are ensuring that risk of infection is minimised for our sheep and for the animals on properties nearby."
All staff and visitors to the garden at Ardingly arriving in vehicles will have to drive over disinfectant-infused straw matting.
Those on foot will have to walk over foam mats at all entrance points to the garden.