Potato plant development can be divided into five key phases: Sprout development, Vegetative growth, tuber initiation, tuber filling (bulking), and maturation.

Sprout development: After planting, sprouts that may already be present on the tubers begin to develop further, while roots also form. Depending on soil temperature, the physiological state of the seed potatoes, and the variety, this phase typically lasts two to three weeks until the sprouts surface and leaves start to develop on the stems. During this period, both the potato haulms (leaves and stems) and roots grow rapidly.

Vegetative growth: Most potato varieties begin to form flower buds between five and seven weeks after emergence. While early maturing varieties may not flower as much, many others will produce flowers multiple times throughout the growing season. However, the falling off of flower buds in some varieties doesn’t impact yield significantly, so there’s no need for removal in the field.

Tuber Initiation: Tuber formation usually occurs four to five weeks after planting, especially in early-maturing varieties. However, this process can be delayed by high nitrogen levels and elevated nighttime temperatures, particularly affecting late-maturing varieties, which may experience even longer delays and result in fewer tubers.

Tuber Filling (Bulking): As the tubers begin to fill, the growth rate of the haulm slows down, although it continues at a reduced pace if there is adequate moisture and nitrogen available.

Maturation: Actual maturation starts when the haulm begins to fall over. Maintaining sufficient nitrogen and moisture in the soil is crucial to prevent the early dying of the plants. Allowing enough time for the crop to mature results in well-developed tuber skins, which help prevent damage and bruising during harvesting, ultimately aiding in better storage outcomes.

Source: https://www.agroberichtenbuitenland.nl/landeninformatie/kenia/achtergrond/events/launch-of-the-potato-signals-2021