Following a promotion on local Welsh potatoes, the retailer said sales shot up by 40% across its 15 stores.
The move was part of a local sourcing drive which saw Pembrokeshire potatoes brought into stores and clearly labelled with the Welsh flag.
The potatoes were supplied by Puffin Produce, based in Haverfordwest in Dyfed.
The move tied in with a promotional campaign to celebrate home-grown produce.
Glyn Hughes, produce manager, said: “We have seen dramatic uplifts in sales as more and more customers buy into local produce, which is of course great news for Welsh farmers.”