Growing Quality Potatoes in Alberta Tuber Initiation and Growth Tuber initiation or tuberization starts when tubers begin to swell at the ends of stolons. This occurs between early June and mid-July in Alberta, depending on location, planting date, climate, soil type, and cultivar.
Tubers form when the plant produces more carbohydrates than are required for vine growth.
Varying climate and moisture conditions cause uneven tube set and growth. The number of tubers formed per plant is called tuber set. Some of the small tubers that are initially set are used by the growing plant and the number that are finally retained and grow is directly related to available moisture and nutrition. Optimum moisture and nutrient levels are therefore critical to the maintenance and development of tubers very early in the growing season. The effect of uniform high levels of moisture has been well documented in Alberta.