At around 7pm on 26 October, three men approached two employees, took their car keys then forced one of them into the garden centre and made him open the safe.
The offenders stole cash and gift vouchers before leaving in the car, a silver Mercedes.
Elston Lewis Clarke, 18, from London, Sidi Mohammed Hauzi, 30, from Aylesbury, and a 17-year-old boy, also from Aylesbury, were charged with robbery on 27 October and appeared at Aylesbury Magistrates' Court.
Clarke and Hauzi were both remanded in custody and the 17-year-old was released on conditional bail until they appear at Aylesbury Crown Court on 10 November.
Security company B to B Links may now install monitored CCTV at the centre.
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