Potato

Potatoes (Solanum tuberosum) are one of the more reliable high-yield crops in the home garden. A single seed piece - a cut chunk of certified seed potato - typically returns 5–10 pounds of tubers. At $1.25/lb retail (USDA ERS, Vegetables and Pulses Yearbook, 2023), that’s $6–$12.50 per planting hole. Fingerling and purple varieties at specialty and farmers market prices of $3–$5/lb change that math considerably.

The catch is that potatoes want a lot of space and need proper seed stock. Starting from grocery store potatoes seems logical - they’re cheap and widely available - but most commercial potatoes are treated with sprout inhibitors (chlorpropham/CIPC) and may carry viral diseases not visible to the eye. Certified seed potatoes from a nursery or seed company are tested for disease and are the correct starting material.

What you’re choosing between

Russets (Burbank, Ranger) are the baking/frying standard. Long-season types, usually 90–120 days. Good for storage.

Red-skinned types (Red Norland, Red Pontiac) are early-season (65–80 days), waxy-fleshed, good for boiling and salads. Less starchy than russets.

Fingerlings (Russian Banana, French Fingerling, Purple Peruvian) are small, elongated, waxy-fleshed. These bring $3–$5/lb at farm stands and specialty grocers (USDA AMS Specialty Crop Market News, 2023). They’re the right variety if you’re growing for sale or trying to maximize value per square foot.

Purple and blue types (All Blue, Purple Viking) have anthocyanin-rich flesh, distinctive flavor, and specialty market appeal in the same $3–$4/lb range.

Early types (Yukon Gold, Irish Cobbler) mature in 65–70 days and are often the best choice for short-season climates or for getting a harvest before late blight season peaks in humid regions.

The ROI case

Certified seed potatoes run $4–$8 per pound ($4.99 typical for a 2 lb bag). One pound of seed potato cut into 1.5–2 oz pieces with at least one eye each yields roughly 6–8 seed pieces. At 5 lb average return per seed piece (University of Maine Cooperative Extension, Potato Production, 2022), one pound of seed potatoes returns 30–40 lbs of harvest. At $1.25/lb, that’s $37–$50 per pound of seed input.

The economics look better with specialty varieties. Russian Banana fingerlings at $4/lb and 40 lbs returned from a $5 bag of seed: $160 in value. That’s the case for growing specialty types even if you don’t sell at market - the premium per pound is real at the grocery store too.

Growing requirements

Plant when soil temperature reaches 45–55°F consistently - typically 2–4 weeks before last frost date in most zones (Penn State Extension, Commercial Potato Production, 2020). Potatoes tolerate light frost after emergence, but a hard freeze will kill emerged shoots. In areas with late frosts, have row cover ready.

Soil pH of 5.0–6.5. This is noticeably more acidic than most vegetables. The lower pH range is intentional: it suppresses Streptomyces scabies, the bacterium that causes common scab, which thrives above pH 6.5. In alkaline soils, scab causes cosmetic corky patches on tubers that don’t affect flavor but reduce market value significantly.

Hilling is not optional. As plants grow to 6–8 inches, mound soil up around the base, burying the lower stems. Tubers form on underground stolons along the buried stem. Hilling also prevents tubers from being exposed to sunlight. Exposed tubers turn green (solanine production), which is mildly toxic - those portions should be cut away and not eaten. Hill twice during the season; the first hill at 6 inches of growth, the second 2–3 weeks later.

Potatoes are heavy potassium and phosphorus feeders. Work in compost and a balanced fertilizer before planting. Do not apply high-nitrogen fertilizer late in the season - excess nitrogen at tuber initiation stage pushes foliage and produces small tubers.

Water consistency matters specifically for preventing hollow heart - a brown cavity that develops at the center of the tuber when rapid water uptake follows a dry period, causing rapid internal expansion that outpaces the cell walls. Keep soil moisture even, especially from tuber initiation through sizing (Purdue Extension, Potato Disorders: Hollow Heart, BP-69).

What goes wrong

Late blight (Phytophthora infestans) is the defining potato disease. This is the same oomycete that caused the Irish Famine. Water-soaked, greasy-looking lesions on leaves and stems spread rapidly in cool (60–70°F), humid, wet weather. White sporulation appears on leaf undersides. An infected plant can collapse within days in favorable conditions. There is no cure once blight is established. Pull and bag affected plants immediately; do not compost. Resistant varieties (Defender, Elba, Kennebec) are worth growing in the humid Northeast where late blight pressure is severe. Scout every 3–4 days during wet weather.

Common scab (Streptomyces scabies) produces rough, corky patches on tuber surfaces. It’s primarily a cosmetic defect but reduces value if you’re selling. The main prevention is maintaining soil pH below 6.5 and avoiding manure application to potato beds (which raises pH and bacterial activity). Resistant varieties exist but are limited in selection.

Colorado potato beetle (Leptinotarsa decemlineata) is a striped yellow-and-black beetle whose larvae defoliate plants with impressive speed. Hand-pick egg masses (yellow-orange clusters on leaf undersides) and larvae. Bt var. tenebrionis (Bt-T) is effective against larvae. Rotate crops - beetles overwinter in soil and re-emerge near where they fed the previous year.

Wireworms (larvae of click beetles, family Elateridae) are slender, hard-bodied larvae that bore into tubers, producing tunnels that create entry points for rot. They’re worst in beds recently converted from lawn or sod. Crop rotation and avoiding planting in recently tilled sod areas reduces wireworm pressure.

Harvest and storage

New potatoes can be harvested 2–3 weeks after plants flower - carefully dig alongside the plant and remove some tubers, then re-mound and let the plant continue growing. These are immature, thin-skinned, excellent for immediate cooking but they don’t store.

For full harvest and storage: wait until plants yellow and die back naturally. The foliage dying is the signal that the tubers have set their skins. Leave tubers in the ground for 1–2 weeks after die-back (as long as soil isn’t waterlogged) to allow skins to cure and harden. Then harvest carefully with a fork, avoiding puncturing tubers.

Cure at 50–60°F in high humidity for 2 weeks. This heals any cuts and completes skin set. After curing, store at 38–40°F in high humidity and darkness. Temperatures below 38°F convert starches to sugars (producing a sweet, off flavor when cooked); temperatures above 50°F accelerate sprouting. Light exposure triggers solanine production even on properly cured tubers.

Well-cured storage varieties keep 4–6 months. Fingerlings and thin-skinned red types store 2–3 months.

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Related crops: Green Bean, Winter Squash

Related reading: Raised Bed Break-Even - how to model long-season crops like potatoes when calculating bed payback period