Potatoes are grown from pieces of potato, not from botanical seed. A seed potato is simply a certified disease-free tuber that you cut into sections, each with at least one eye, and plant those pieces. This distinction matters because using grocery-store potatoes — which may be treated with sprout inhibitors and carry unknown diseases — often leads to disappointing results. Certified seed potatoes from a reputable supplier are worth the price.
Plant 2 weeks before your when soil is at least 45°F and has dried out enough to work without compacting. Dig a trench 4 to 6 inches deep, lay seed pieces 12 inches apart with the eye side up, and cover with 3 to 4 inches of soil. Chitting — setting seed potatoes in a warm, bright spot for two to three weeks before planting so the eyes begin to sprout — can accelerate emergence and is worth doing if you have the space and lead time.
Hilling is the defining maintenance task. As vines emerge, mound soil or straw up around the stems, leaving only the top 4 to 6 inches of green growth exposed. Repeat every few weeks as vines grow. This does two things: it increases the underground stem length where new tubers form, which can meaningfully increase yield, and it keeps forming tubers covered from light. Any tuber exposed to sunlight turns green and accumulates solanine, a mildly toxic glycoalkaloid. Green potatoes should not be eaten.
Common scab — rough, corky patches on the skin — is the most frequently encountered problem and the most misunderstood. It's caused by Streptomyces bacteria in the soil, not a fungus, and it thrives in soil with a above 6.5 and dry conditions during the six weeks after planting. Keeping pH in the 5.5 to 6.5 range and maintaining consistent moisture during tuber initiation tends to reduce incidence significantly. Scab is cosmetic — peel it off and the flesh underneath is fine — but it's disheartening to dig a bed you've worked all season and find rough, scarred tubers.
Stop watering about two weeks before you plan to harvest to let the skins cure in the ground. The tops dying back is the signal that the tubers are mature; early varieties like Yukon Gold die back at 70 days, late varieties like Russet Burbank at 120. Dig carefully with a fork rather than a spade — a stabbed tuber will rot quickly. Cure in a cool, dark, humid space for one to two weeks before moving to long-term storage at 38 to 40°F. Yukon Gold and Red Pontiac store for months; German Butterball may keep even longer in ideal conditions.
Varieties worth knowing
What can go wrong
Companions
How to propagate
Potatoes are propagated vegetatively by planting seed potatoes (tubers), not by botanical seed. Each tuber or tuber piece with at least one or two eyes will sprout into a new plant.
Harvest & keep
Hill up soil or mulch as plants grow — tubers form along the buried stem. New potatoes: dig at flowering; storage: wait until vines die back.
- Refrigerator
- do not refrigerate — cold turns starch to sugar, blackens when cooked
- Freeze
- blanch fries or mashed, then freeze
- Can
- pressure can only (whole small or cubed)
- Dry
- slice and dry at 125°F for soup and hash
- Cure
- Cure freshly dug tubers 1–2 weeks in darkness at 50–60°F, 85% humidity — heals skins.
- Root cellar
- store in total darkness at 35–40°F, 90% humidity — 4–8 months depending on variety
Green potatoes contain solanine — discard. Keep stored potatoes completely dark or they'll green.
How it grows where you live
Sources
- Potato Production in Home Gardens— University of Minnesota Extension
- Growing Potatoes in the Home Garden— Penn State Extension
- Late Blight of Potato and Tomato— Oregon State University Extension
- Why are the edges of my older leaves turning brown and scorched-looking while the centers stay green?Marginal leaf scorch on lower, older leaves — a brown or yellowing burn along the leaf edge — is a characteristic sign of potassium deficiency, which also tends to produce weak stems and poor fruit quality.
- When and how should I adjust my soil pH, and how long does it take to work?pH amendments work slowly — sulfur and lime both take weeks to months to shift pH — so the most effective time to apply them is in fall or at least 6–8 weeks before planting, not at planting time.