The plastic cards trialled in July this year to test integration of Corby & Fellas and Davidson Richards Epos systems.
The HTA says the trial worked so a wider trial will take place in the first quarter of 2016.
Meanwhile, lily of the valley, sweetpea, jasmine, cherry tree blossom and bluebell are to feature on new voucher designs for 2016, taking inspiration from the most popular plants in David Domoney's positive power of plants 2015 Chelsea Flower Show exhibit.
Some 89.3 per cent of vouchers are sold in garden centres. Average spend is £27, with 50 per cent more spent at the till.