The potato plant, Solanum tuberosum, is one of the world’s most important food crops. New gardeners often become confused when asking if they can buy potato seeds, as the plant produces two distinct forms of propagation. Most gardeners are familiar with the small potatoes sold for planting, but the plant also produces true botanical seeds, much like its relative, the tomato. Understanding this difference is key to successful potato gardening.
Defining Potato Propagation: Tubers and True Seeds
The method most commonly used involves planting a seed potato, a specialized tuber. This tuber is an enlarged portion of the plant’s underground stem, designed to store energy and reproduce asexually. Planting a seed potato creates a genetic clone of the parent plant, ensuring the resulting harvest is identical in characteristics like color, shape, and flavor.
In contrast, the potato plant also reproduces sexually by producing flowers. When pollinated, these flowers develop small, green fruits containing True Potato Seeds (TPS), the plant’s actual botanical seeds. TPS result from sexual reproduction, carrying a mix of genetic material from two parents. Seed potatoes offer genetic consistency, while TPS offers genetic diversity.
Growing Potatoes from True Potato Seed
TPS is often employed by plant breeders to develop new varieties. Growing potatoes from TPS is similar to starting tomatoes or peppers, requiring the seeds to be sown indoors six to eight weeks before the last frost date. The small seeds are slow to germinate, needing constant temperatures around 70°F and bright light.
A major advantage of TPS is its easy storage and transport compared to bulky tubers, remaining viable for several years. TPS are generally free from the viruses that accumulate in tuber stock, offering a clean start for the crop. Once seedlings are about two inches tall, they are transplanted into the garden like small tomato plants.
The resulting crop exhibits high genetic variation; every seedling is unique, and the tubers produced vary widely in size, shape, and color. While non-uniformity is a disadvantage for commercial growers, it offers an opportunity for the experimental gardener. A crop grown from TPS produces small tubers in the first year, and it generally takes two growing seasons to yield full-sized potatoes.
The Standard Method: Planting Seed Potatoes
The majority of potatoes are grown from seed potatoes, which are small, certified disease-free tubers. This vegetative propagation method is favored because it ensures the grower harvests a crop genetically identical to the parent variety. The process is straightforward: the tubers are often “chitted,” or pre-sprouted, in a bright location to encourage sturdy shoots from the “eyes.”
The tubers are then planted whole or cut into chunks, ensuring each piece contains at least one or two developing sprouts. This method offers rapid growth and predictable yields, resulting in a full harvest of mature tubers in a single growing season, usually 90 to 120 days. This consistency and speed are necessary for commercial agriculture.
The main drawback to relying on tubers is the risk of disease transmission. Viruses and pathogens accumulate in the vegetative tissue over successive generations, and planting an infected seed potato introduces that disease directly into the new crop. Certified seed potatoes, tested to be free of common potato diseases, are highly recommended over using grocery store potatoes.
Choosing the Right Starting Material for Your Garden
The choice between True Potato Seed (TPS) and seed potatoes depends entirely on the gardener’s goals. If the priority is a quick, reliable harvest of a known variety, planting certified seed potatoes is the practical option. This method provides a predictable outcome with mature, uniform tubers ready for harvest within a few months.
If the goal is long-term storage, easy shipping, or experimenting with new varieties, TPS is the better choice. TPS offers superior genetic diversity, potentially leading to discovering a new potato adapted to the garden. However, this path requires a longer initial time investment and accepting a wide range of tuber characteristics in the first year.