After you plant a seed potato, it goes through the five potato growth stages: sprout development, vegetative growth, tuber growth, tuber bulking, and maturation.
The video below will give you an understanding of those stages.
Potato Growth Stages
Stage 1: Sprout Development
After the seed potato or piece is planted, the piece provides nourishment for a sprout or seedling to grow. The eyes of the potato develop sprouts. The sprouts grow and emerge from the soil. Depending on the climate, shoots and stems rise from the ground two to six weeks after planting. A main stem and the first leaves begin to grow. The root system develops quickly and begins to absorb nutrients as the starch in the seed piece gets used up.
Stage 2: Vegetative Growth and Photosynthesis
The leafy part of the plant puts on a lot of growth over four or five weeks. With proper sunlight, photosynthesis begins in the leaves and stems above ground. Excess energy is channeled downward as stolons (underground stems or “tubers”) develop. These tubers develop above the original seed piece, not below it. The tubers grow out from the entire length of the underground stem, starting at the bottom to the uppermost section of the buried stem—the short underground stems (what we call potatoes) store nutrients. Soon, the plant’s main stem will stop growing and produce a flower bud.
Stage 3: Tuber Growth
Tubers begin forming on the end of stolons; the stolon tips swell, and tubers start to form. Above ground, shoots develop ahead of flowers. Stolons usually swell before the plant flowers. (Because the “root” of the potato plant is a stem, not a root, potatoes are considered tubers.) Tuber development begins 5 to 6 weeks after sprouts emerge from the soil. When a potato plant flowers, that is a sign that the nutrient process and tuber development have begun underground. (But it’s important to note that some potato varieties produce potatoes without flowering.)
Stage 4: Tuber Bulking
Tubers enlarge. Sugars and starches accumulate in the newly formed tubers. Optimal soil moisture and temperature and the availability of soil nutrients are very important during this time for the best yield. Tubers form best in cooler temperatures. The best crops are produced when the daytime temperature is 60° to 65°F range and night temperatures are below 57°F. Fewer tubers form when temperatures are between 68° and 84°F, and no tubers form when temperatures are greater than 84°F. (When the weather is warm, the top part of the plant respires heavily, reducing the nutrients that can be stored in the tubers below ground.)
Stage 5: Maturation
As starch is stored in the tubers underground, the tubers enlarge and reach full size. The outside layer of the tuber gets tougher and tougher, keeping moisture within the potato. As the tuber skins harden, the leaves and stems above ground dry out and die. Potatoes can remain underground for a while after the tops begin to die, so the last energy in the foliage is transferred to the tubers. When the top of the plant dries out and yellows, tubers are ready for harvesting. The harvest of mature tubers can begin 10 to 26 or more weeks after planting (70 to 120 days), depending on the variety. Harvest potatoes at any size (Wait until the challenge day.) Potatoes will store well if their skin does not rub off easily.