So back at the end of August C and I planted our Christmas potatoes and a couple of weeks ago they were ready to be earthed up. Earthing up basically means putting soil (compost ideally) on top of the foliage that has sprouted from the potatoes. You can completely cover it and it will keep growing through the new soil. Earthing up can be done more than once as well. Why earth up potatoes? Simply, to increase the yield. The more depth of soil, the more space for potatoes to grow.
So basically once the potato foliage has grown to about 15cm then cover them with earth just up to the top of the foliage. Then once they’ve grown to the same height again then repeat. I would probably only earth up twice to then give the chance for the foliage to develop and enable it to concentrate on fattening up those tubers. If you have your potatoes in bags like me (which ideally all potatoes grown at the time of year should be) then you can earth up to the top of the bag. Remember though that bags are pretty hard to move when full so try to get them in their final position (a greenhouse or conservatory by mid October) before earthing up.
Mine can probably have a tiny bit more earth in but not much really. Next thing to watch out for potato-wise is the flowers…hoping they appear by about mid October. Does anyone else grow Christmas potatoes? How are they getting on?