Do Potatoes Grow Above the Ground?

Potato Growth Stages

The development of a potato plant is a process that begins with sprouting and ends with the maturation. Once the plant establishes itself, tuber production begins, and the tubers spend several weeks manufacturing the starches that cause them to grow. Temperature, soil conditions, moisture and location each play a role in the rate at which a potato plant develops and matures. The potato tuber used for planting, also called the mother tuber, is actually a large stem that produces eyes, or dormant buds, that will eventually develop into side stems and leaves.

Once the potato plant is established and vegetative growth has begun above-ground, the potato root stems grow into stolons, which enlarge into tubers of different sizes with an average weight of around 10 ounces. The stolons produce hooked ends that evolve into tiny potatoes. If the plants are exposed to too much heat, the hooked ends will result in a leafy shoot instead of a small tuber. The first flowers often appear on the plant to coincide with the new tubers forming below the soil. The plant's true roots eventually develop from the remnants of the old tuber once the stems and stolons have started to produce new tubers.

As the potato plant's foliage goes through the process of photosynthesis, water, nutrients and carbohydrates are absorbed by the new tubers, initiating an extended growth spurt as their cells expand. The bulking stage is the longest of all the growth stages, sometimes lasting as long as three months.

The number of tubers that a potato plant produces is governed by several factors, including the availability of moisture. While too little moisture can impact tuber production and cause problems such as premature plant death and knobby tubers, too much moisture can result in waterlogged soil and inadequate aeration of the soil, as well as enlarged openings in the potato skins that can promote disease and tuber decay in storage. While a potato plant can set as many as 20 to 30 tubers initially, only 5 to 15 usually reach maturity, states the Manitoba Agriculture, Food and Rural Initiatives. The plants actually absorb some of the new tubers during the growth period.