Cultivation begins when the seed potato tuber is planted in the spring. Both roots and stalks grow from this potato. New small tubers will develop on some of the roots. Plenty of water and nourishment are essential in order for the newly formed tubers to grow. Sun is also important for the plant, since this is the source of the starch that is stored in the potato tuber.
The green plant parts of the potato plant rising above the ground are called tops or haulm. These are vital as they capture the sunlight used as energy by the plant. This in turn is used not only to support metabolism, but also to enable new leaves and tubers to develop and grow. The extra energy the plant does not need is stored in the tubers as reserve energy, which is then extracted as starch at the factories