Russet potatoes, known for making fluffy baked potatoes and crispy fries, are valued for their high starch content, netted skin, and excellent storage capabilities. This variety is categorized as a late-season or maincrop potato, demanding a long growing period compared to early-season types. The total time from planting the seed potato to harvesting the fully developed tuber is a matter of months, not weeks, which is a key consideration for growers.
The Standard Growth Timeline for Russet Potatoes
Russet potatoes typically require 100 to 130 days from planting to reach the full maturity needed for their signature characteristics. This extended timeline allows the tubers to accumulate the high levels of starch and density that define a quality Russet. The exact number of days can fluctuate depending on local climate conditions, such as soil temperature and moisture, and the specific cultivar.
Two common Russet varieties illustrate this variation in maturity time. The widely grown Russet Burbank is a late-maturing cultivar, often requiring 120 to 150 days to achieve maximum yield and quality for long-term storage and processing. Conversely, the Russet Norkotah, popular for the fresh market, matures earlier, typically in the range of 95 to 110 days from planting.
Smaller, immature tubers, referred to as “new” potatoes, can be harvested sooner, around 70 to 80 days after planting. These small potatoes have delicate, thin skins and a waxy texture. However, they lack the dense, mealy interior and thick skin necessary for the classic Russet baking texture and long-term storage, requiring the full 100-plus day maturation period.
Essential Milestones in Tuber Formation
The Russet’s growth cycle is divided into distinct biological stages, beginning with sprouting and emergence above the soil. The first stage, known as vegetative growth, focuses on establishing the stems, leaves, and root system, lasting anywhere from 30 to 70 days. A larger plant canopy created during this time translates directly to a greater potential for tuber yield.
Tuber formation, or “tuber set,” begins around the time the plant starts to flower, typically 60 to 70 days after planting. During this two-week window, the plant initiates the formation of stolons, the underground stems where new tubers will swell. Hilling, the practice of mounding soil around the base of the plant, protects developing tubers from sunlight, preventing them from turning green.
Following tuber set is the “bulking” phase, where existing tubers rapidly increase in size and density, accumulating starch and dry matter. This is the longest phase of the Russet’s growth, lasting until the plant naturally begins to senesce, or die back. The final size and high specific gravity of the mature Russet are achieved during this stage, determining the final quality of the potato.
Knowing When to Harvest Mature Russets
The clearest indication that the Russet’s growing cycle is complete is the natural dieback of the plant’s foliage. Once the 100 to 130 days are nearing an end, the green vines and leaves will begin to yellow, brown, and collapse as the plant diverts energy into the underground tubers. Waiting until the tops are completely brown and dead ensures the potatoes have reached maximum size and starch content.
The period after vine dieback is when “skin set” is finalized, indicating a mature Russet ready for storage. The skin of a fully mature potato will be thick and firm, resisting easy removal when rubbed with a thumb. Harvesting before the skin is fully set results in thin-skinned tubers prone to bruising and poor storage quality.
After digging the mature tubers, a final step is necessary to prepare them for long-term storage. This involves a curing process, where the potatoes are held in a cool, dark, and humid environment for ten to fourteen days. Curing allows minor wounds on the skin to heal, further toughening the outer layer and extending the Russet’s shelf life.