If it has been dry where you live the problem is that there is a lot of dry fibre in the potato tubers. When you cook them they absorb far more water than usual and turn into mush. You can try steaming them to help solve the problem.

No problem except I have had a very small harvest..Tasty but small..

Thanks to both Moon grower and Cazzalyn - Yes surprise, surprise we did a very dry spell in Wales - thought i was pouring water on but obviously not up to Natures normal supply!