When searching to buy potatoes for planting, look for “seed potatoes.” Potatoes purchased for consumption in a grocery store are not the same product, even if they sprout. Table stock potatoes are commonly treated with chemical sprout inhibitors to prolong shelf life, preventing them from successfully growing once planted. Planting stock must be explicitly grown and inspected for propagation.
Understanding Seed Potatoes
Seed potatoes are small tubers specifically grown to be disease-free for planting, providing a healthy start for the crop. Unlike table potatoes, they are never treated with sprout-inhibiting agents, ensuring they break dormancy to produce new plants. Planting a non-certified potato risks introducing soil-borne diseases and viruses that can persist for years. These pathogens, which may not be visible, can significantly reduce the yield and quality of future potato harvests.
“Certified” means the seed potatoes have undergone a rigorous inspection process by agricultural authorities. This certification confirms the variety is true to type and has been tested for common potato diseases like late blight tuber rot, nematodes, and bacterial ring rot. Seed growers cultivate these tubers in areas with low pest pressure and submit samples for laboratory testing to ensure purity and health. This inspection provides assurance that the planting material is free from viral diseases that diminish crop vigor over time.
Seed potatoes are categorized by their maturity time, which determines the harvest window. First early varieties mature fastest, ready for harvest within 60 to 90 days after planting. Mid-season or second early varieties mature between 90 and 120 days. Maincrop or late-season potatoes require the longest growing period, maturing between 120 and 150 days, and are the best choice for long-term storage.
Retail and Online Sources for Planting
The most reliable source for a diverse selection of planting material is a mail-order catalog or an online seed specialist. These vendors carry a wider array of unique, heirloom, and specialized potato varieties not found in local stores. Ordering online allows the gardener to secure preferred varieties early, though shipment may be delayed until the appropriate planting time. These specialists consistently offer certified stock and provide detailed growing information specific to each variety.
Local garden centers and nurseries are an excellent source, offering immediate availability and personal advice. Purchasing locally allows the gardener to inspect the physical tubers before buying and discuss regional growing challenges with knowledgeable staff. While the selection may be smaller than online catalogs, the stock is generally certified and suitable for local growing conditions. Gardeners should always look for a certification tag or label, regardless of the vendor.
Agricultural supply stores and farm co-operatives also sell certified seed potatoes, often in larger quantities appropriate for bigger gardens or small farms. These sources focus on high-yielding, established varieties popular with commercial growers. While these vendors are generally trustworthy, confirming the certification status of the seed lot is prudent. Checking the product packaging for a blue tag or an official state certificate confirms the stock has passed the necessary health inspections.
Timing Your Purchase and Receiving
Seed potatoes are a seasonal item, and the timing of purchase is often counter-intuitive for new gardeners. Many online suppliers and mail-order companies begin offering pre-orders in late fall or early winter. Placing an order early is recommended to ensure the availability of popular or limited varieties before they sell out. Shipment usually occurs in late winter or early spring, timed to arrive close to the optimal planting window.
Once the seed potatoes arrive, unpack them immediately to ensure proper air circulation and prevent rot from moisture buildup. The tubers must be stored in a cool, dark, and frost-free location, such as a garage or basement, until four to six weeks before the anticipated planting date. Temperatures above 50 degrees Fahrenheit can cause premature sprouting, resulting in weak, elongated shoots that break easily upon planting.
The process of “chitting,” or pre-sprouting, involves moving the tubers to a cool area with indirect light about a month before planting. Place the potatoes in a single layer, often in egg cartons or shallow trays, with the “eyes” facing upward. This encourages the development of short, stubby, dark green sprouts. These robust sprouts give the plant a faster start once in the soil and can accelerate the harvest by up to two weeks. The ideal sprout length at planting time is approximately one inch.