Alternatively, the plants can be mulched with a thick layer of hay, straw, leaf-mould or grass mowings. This will have the added benefit of conserving moisture. See also our factsheet on Growing potatoes without digging Soil moisture and watering Potatoes use a lot of water. For the highest yield of good-sized tubers, keep the soil moist throughout the season. Manure, compost and leafmould will all help your soil to hold more water.
Varieties vary in their drought tolerance.
The most effective stage at which to water, where necessary, is when the tubers are the size of marbles. This usually coincides with flowering. Water the soil rather than the foliage. Flowering is usually a good indicator that the tubers have reached an edible size, but not all varieties produce flowers. If the crop is being damaged by pests, lift them earlier.