From Little Potatoes meals grow
The potatoes from the allotment have been used in this weeks lunches. There were some tiny potatoes in there which we will be using as seed potatoes, we will replant them and these tiny little potatoes will hopefully give us a big crop for next season.
How to grow potatoes from seed
It's important to 'chit' the seed potatoes first before planting; this means allowing them to start sprouting shoots. Stand them rose end up (the rose end is the one with the most small dents in the skin, or 'eyes') in egg boxes or similar in a light, frost-free place. The potatoes are ready to plant when the shoots are about 3cm (1in) long.
See https://www.rhs.org.uk/advice/grow-your-own/vegetables/potatoes for the next step.