Growing potatoes begins with the potato tuber itself, using its natural ability to sprout a new plant from a structure called an “eye.” The potato eye is a dormant bud that serves as the starting point for vegetative propagation. While this is the standard method for cultivation, the total time from planting to harvest is highly variable. The final timeline depends significantly on the specific potato variety chosen—classified as early, mid-season, or late-season—and the local climate conditions after planting.
Preparing Seed Potatoes Before Planting
Preparing the seed potato piece influences the speed of emergence and overall plant health. If the seed potato is larger than a small egg, cut it into pieces, ensuring each section contains one to three healthy eyes. Each piece should weigh roughly 1.5 to 2 ounces to ensure enough stored energy for initial growth.
After cutting, the pieces must be cured for 24 to 48 hours, or up to five days, by drying them in a warm, well-ventilated area. This curing process forms a protective, cork-like layer over the cut surface, which helps prevent the seed piece from rotting once it is planted in the soil.
Another technique, known as “chitting,” involves placing the seed potatoes in a cool, bright location for two to three weeks before planting. Chitting encourages the eyes to sprout short, sturdy shoots before they are placed in the ground. This step can significantly reduce the total growth cycle, as properly sprouted potatoes establish roots faster than dormant tubers.
Key Stages of Potato Growth and Timing
Once planted, the potato growth cycle proceeds through distinct phases that determine the time required to reach maturity. The first stage is sprouting and emergence, which typically takes two to four weeks before the first green shoots break the soil surface. Soil temperature is a major factor, and cold ground can delay emergence, sometimes taking up to 25 days.
Following emergence, the plant enters a period of rapid vegetative growth lasting approximately 30 to 50 days. During this time, the plant develops a robust canopy of foliage and a strong root system. The third phase is tuber set, where the stolons—underground stems—swell at their tips to begin forming the new potatoes.
The length of the final stage, tuber bulking, determines the potato’s classification and total time to harvest. Early-season varieties require 60 to 90 days from planting to reach a harvestable size. Mid-season varieties require 90 to 110 days, while late-season potatoes need 110 to 140 days to fully mature.
Determining When Potatoes Are Ready for Harvest
The timing of the harvest depends on the desired size and intended use of the potatoes. Small, thin-skinned “new potatoes” can be harvested relatively early, often just seven to eight weeks after planting. This initial harvest usually occurs shortly after the plant has flowered while the foliage is still green.
To harvest new potatoes, a gardener can carefully reach into the soil around the plant’s base and remove a few small tubers without disturbing the main root system. For a full crop of mature potatoes meant for storage, wait until the plant signals the end of its life cycle. This indicator is the natural yellowing and complete dieback of the above-ground foliage.
Once the tops have died back, the potatoes are typically ready for digging two to three weeks later. This waiting period allows the skin to fully “set” and toughen. Before the final harvest, the plant should not be watered for a couple of weeks to facilitate this skin-setting process. After they are gently dug from the soil, mature potatoes benefit from a curing period of 10 to 14 days in a cool, dark, and humid environment to heal minor surface wounds and ensure optimal long-term storage.