There is no need to chit seed potatoes which are planted in summer, so just plant them straight out into trenches dug into a well-prepared bed about 30cm (12") apart, or plant them into a potato grow-bag, making sure there is at least 20cm (8") of compost beneath them. Add a general purpose fertiliser to the bottom of the trench or growbag and then cover the potatoes with a 20cm layer of soil or compost. Keep well watered and as the plants get to around 20cm (8") tall you need to bank up the soil around the plant, so the soil covers the bottom two thirds of the plant. Watering your plants well will help improve crop yield and discourage potato scab. It is important that the crop is protected from frosts and the crop should be ready to harvest in around 12 weeks.