Quick facts
| Fact | Figures given |
|---|---|
| Frost tolerance | Half-hardy: tolerates light frost but not heavy frost or freezing (UMD); "semi-hardy" (CSU) |
| Sun | At least 6 hours of direct sun, 8–10 preferred (UMD); 6–8 hours for containers (UNH) |
| Soil pH | 6.0–6.5 (UMD, UMN, Penn State); 4.8–5.8 where scab persists (UMD) |
| Days to maturity | 90–120 (UMD); 100–120 (NC State); 125 typical (CSU) |
Seed potatoes and seed pieces
- Certified seed. Disease-free tubers from a certified grower (UMN, UMD, Penn State). Grocery potatoes may carry disease (UMD) or be treated to stop sprouting (UNH, Penn State); saved tubers may carry disease (UMN).
- Seed piece. A whole small tuber, or a cut chunk of a larger one, with at least one eye.
- Eye. A bud on the tuber; Penn State calls the sprouts that grow from eyes "chits".
- Green sprouting. For an earlier start, sprout whole tubers in the dark at room temperature, then move them into light to keep sprouts short (UMD).
- Use firm, unsprouted seed; wilted or sprouted seed has less vigor (UMD).
- Plant small tubers whole: 1–1¼ in across (UMN) or 1–1½ in (Penn State).
- Cut larger tubers with a clean knife. UMD: 1½-in cubes of about 1½–2 oz, each with 1–3 eyes. UMN: 1¼-in chunks with at least one eye, two or three better. UNH: 1–2 in pieces.
- Let the cut surfaces dry before planting: a few days at 60–70°F (UMN, Penn State) until a tough protective layer forms (UMN), or a day or two (UNH). Drying reduces rot (UMD).
When, how deep, how far apart
| Source | When | Depth | In the row | Between rows |
|---|---|---|---|---|
| UMD | March 15–May 1 depending on location, early varieties through June 1; soil at least 45°F | 3–5 in, cut side down; later crops 5–6 in | 8–12 in; about 9 in for new potatoes, up to 20 in for large storage potatoes | 24–36 in |
| UMN | As soon as the soil warms: early April in the Twin Cities, possibly not until May in the north | 3–5 in, cut side down, covered with 4 in of soil or compost | 10–12 in | 30–36 in |
| Penn State | When soil reaches 45°F | 4-in trench, sprouts up, 4 in of cover | 8–12 in | — |
| CSU | Soil at 40°F (GardenNotes #719a); minimum 45°F, as early as 0–2 weeks before the average last frost (#720) | 4 in (#719a); 4–6 in (#720) | 12–15 in each way, or three plants across a 4-ft bed | |
Cold, wet soil raises the risk of rot (Penn State, UMD); soil above 80°F inhibits tubers (UMD). For local dates, start from frost dates explained and the planting calendar; grid-bed counts are on square foot gardening spacing.
Hilling
Hilling means drawing soil up around the stems so developing tubers are shielded from sun, which turns them green or scalds them (UMD, CSU).
- Start when stems are about a foot tall (UMN) or 8–12 in (Penn State); UMD hills once the tops are fully grown.
- Mound soil to cover most of the stem (Penn State), then repeat once or twice more (UMN) or two or three times (Penn State), for 6–8 in of soil in total by season's end (UMN).
- Keep hill tops no more than 6 in above grade (UMD).
- Weed-free straw mulch can replace hilling (CSU); after hilling, a thick straw mulch keeps soil cool and moist and deters Colorado potato beetles (UMD).
- 1. Seed piece, cut side down, 3–5 in below grade (UMD, UMN)
- 2. Hill: soil drawn up around the stems as they grow, 6–8 in in total by season's end (UMN); hill tops no more than 6 in above grade (UMD)
- 3. New tubers: kept under soil so light cannot turn them green (UMD, Penn State)
- 4. Container: opaque, with drainage holes, about 2–3 ft tall and 10–15 gal (UNH)
- 5. First layer: 6–8 in of mix, seed pieces about 1 ft apart, covered with about 6 in more (UNH)
- 6. Keep adding mix as the plants grow, leaving about 6 in of foliage showing (UNH)
Containers and grow bags
| Source | Container | Planting and filling |
|---|---|---|
| UMD | 30 gal of potting mix; potato "towers" usually don't work | — |
| NC State | 30 gal minimum, plants 5–6 in apart | — |
| UNH | 10–15 gal, about 2–3 ft tall, opaque, with drainage holes; barrels, bins, tubs, towers or growing bags; about 5 gal of mix per plant | 6–8 in of mix, seed pieces about 1 ft apart, about 6 in more on top; keep adding so about 6 in of foliage shows |
| Penn State | 10–15 gal, opaque, food-safe, with drainage holes, or a tower or grow bag | 4 in of mix, 3–5 tubers eyes up, 3 in on top; add mix until only leaves show, until the container is full |
| Illinois | Any size with drainage; bigger yields more | A few inches of mix, seed pieces covered with 4–6 in; keep adding until only the top leaves show |
- Mix. Potting mix plus compost, not garden soil (UNH, Penn State).
- Height and variety. Taller containers are harder to water evenly (UNH). Mid- or late-season varieties generally do better than early ones, since they keep forming tubers longer (UNH).
- Water. When the top 1–2 in feel dry, until some drains out (UNH); containers dry out faster than beds (Penn State).
- Grow bags. UNH and Penn State list grow bags as an option but give no separate size or method, so the container figures above apply. Containers may yield fewer potatoes than garden soil (UNH).
Other crops: container sizes for vegetables.
Watering
About 1 in of water a week, in one or two soakings (UMN, Penn State). Avoid overhead watering, which can spread fungal disease (UMD, CSU). Wet soil rots tubers and dry soil makes them knobby (CSU).
Harvest, curing and storage
| Stage | Figures given |
|---|---|
| New potatoes | 6–8 weeks after planting, usually once plants flower (UMD); 7–8 weeks (UMN); about 8 weeks, before skins thicken (Penn State) |
| Storage potatoes | Leave in the ground 2 weeks after plants die back so skins thicken (UMD); after plants have dried or tubers reach full size (UMN); after die-back and before a hard frost (Penn State) |
| Curing | 10–14 days at 50–60°F, high humidity (UMD); 10 days or more at 60–65°F, ventilated and dark (UMN); 2–3 weeks at 50–60°F, 85–90% humidity (Penn State) |
| Storage | 40–50°F, about 90% humidity, 6–8 months (UMD); 32–40°F, 95% humidity, 40–50°F for frying potatoes (UMN); 40–46°F, about 90% humidity, not below 38°F, which builds sugar (Penn State) |
Dig with a fork when the soil is not wet, and do not wash tubers before storing (UMD, Penn State). In containers, tip the pot onto a tarp and sift out the tubers (UNH, Illinois).
Green skin contains solanine (UMD) and chaconine, which cause bitterness and, in high amounts, may cause gastrointestinal upset, headache and confusion (Penn State). Cut out green areas (UMD, UMN), do not eat extensively green potatoes (UMN), and do not eat potato sprouts (UMN).
Pests and diseases
- Colorado potato beetle. Adults are about ⅜ in long with ten black stripes on yellowish-white wing covers; yellow-orange eggs sit in clusters of 10–30 under leaves (UMN). Plants tolerate about 30% leaf loss before flowering but only about 10% once tubers size up. UMN lists hand-picking, row covers put on before beetles appear, mulch, and early varieties; the beetle resists over 50 insecticide active ingredients.
- Scab. Dark, rough, corky spots; tubers do not rot and are edible (UMN). Heavy fresh manure or compost can increase it (CSU).
- Blights and wilt. Early blight, late blight and Verticillium wilt (UMN); remove potato debris in fall (CSU).
This page gives no pesticide or fertilizer rates. The UMN and UMD pages linked below discuss products; follow the label and ask your county extension office to confirm a diagnosis.
Where sources disagree
| Topic | Figures |
|---|---|
| Soil temperature to plant | 45°F (UMD, Penn State, CSU #720) vs 40°F (CSU #719a) |
| Container size | 30 gal (UMD, NC State) vs 10–15 gal (UNH, Penn State) |
| Years before nightshades return to a spot | 2–3 (Penn State); 3–4 (UMN); at least 4 (CSU) |
Related nightshades: tomatoes and peppers.
Small-space checklist
- Buy certified seed potatoes, not grocery potatoes.
- Cut large tubers to pieces with 1–3 eyes; let the cuts dry for a few days.
- Plant when soil reaches about 45°F, 3–5 in deep, 8–12 in apart.
- Hill when stems reach 8–12 in, two or three times; or mulch with straw.
- In a container, use 10–30 gal of mix, filled in layers as plants grow.
- Dig new potatoes at 6–8 weeks; cure storage potatoes first.
More crop pages: zucchini, cucumbers, carrots, radishes, bush and pole beans and peas.
Sources
- University of Maryland Extension — Growing Potatoes in a Home Garden (updated 2026)
- University of Minnesota Extension — Growing potatoes in home gardens (Schuh and Tong, reviewed 2026)
- Penn State Extension — Potatoes in the Garden and the Kitchen (D'Aurora and Marquesen, updated 2026)
- University of New Hampshire Extension — What is the best way to grow potatoes in containers? (2020)
- University of Illinois Extension, Hort in the Home Landscape — Growing Potatoes in Containers (Candice Anderson, 2015)
- Colorado State University Extension — Vegetable Garden Hints (CMG GardenNotes #719a, reviewed 2023)
- Colorado State University Extension — Vegetable Planting Guide (CMG GardenNotes #720, reviewed 2024)
- Colorado State University Extension, Colorado Master Gardener — Vegetables (GardenNotes #710–719 compilation, PDF, 2024)
- University of Maryland Extension — Types of Containers for Growing Vegetables
- NC State Extension Gardener Handbook — Chapter 18, Plants Grown in Containers (Table 18-1)
- University of Minnesota Extension — Colorado potato beetle (Schuh, Hahn and Burkness, reviewed 2026)
All sources were opened and checked in October 2026. Rules and figures change; confirm with the original before acting.