General
Potatoes are cool-season tubers grown from certified seed tubers rather than true seed. They prefer cool nights and moderate days and will yield best in loose, stone-free, slightly acidic soil. Early types produce 'new potatoes' in summer, while maincrop types store through winter. Choose blight-resistant varieties for humid summers. Good hilling, even watering, and crop rotation are key to healthy, scab-free tubers.
Light
Full sun (at least 6–8 hours of direct light daily).
Soil type
Loose, deep, well-drained loam or sandy loam enriched with mature compost; avoid fresh manure. Slightly acidic soil reduces common scab.
Water requirement
Moderate but consistent; 25–40 mm per week, more during tuber bulking. Keep evenly moist, not waterlogged.
Nutrient requirement
Medium-high potassium, moderate phosphorus, low to moderate nitrogen. Excess nitrogen causes lush foliage and fewer tubers.
Precultivation
Chit (pre-sprout) seed tubers 4–6 weeks before planting: place in bright, cool conditions (10–15°C) to develop short, sturdy sprouts. Cut large tubers into egg-sized pieces with 2–3 eyes each; let cut surfaces suberize (dry) for 2–3 days before planting. Warm tubers to room temperature just before planting to reduce emergence time.
Planting
Plant when risk of hard frost has passed and soil is workable and above ~8°C. Space rows 60–75 cm apart. Early varieties: 25–30 cm between plants; maincrop: 30–35 cm. Plant 8–12 cm deep in a shallow trench. Hill soil around stems when plants reach 15–20 cm, and again 2–3 weeks later, ultimately building a 20–25 cm ridge to keep tubers covered and reduce greening. Mulch with straw to conserve moisture and suppress weeds.
Pruning
No pruning needed. Pinch flowers only if desired to focus energy on tubers. For storage crops, top-kill or cut vines 10–14 days before lifting to set skins and reduce disease spread during harvest.
Maintenance
Irrigate deeply but infrequently; avoid wet foliage in the evening to limit blight. Side-dress with a low-N, higher-K organic fertilizer at first hilling and again at early tuber set. Keep beds weed-free, especially early. Scout for disease; remove and destroy blighted foliage. Use floating row cover early against beetles/aphids, removing at flowering if needed for airflow. Rotate away from Solanaceae for 3–4 years.
Harvest
For new potatoes, harvest when plants flower or 2–3 weeks after, digging carefully by hand. For mature storage tubers, wait until vines yellow and die back; cut tops and lift 10–14 days later in dry weather. Harvest before the first hard frost. Cure harvested tubers at 10–15°C and high humidity for 10–14 days, then store at 4–6°C in darkness. Brush off loose soil and avoid washing before storage. Handle gently to avoid bruising; exclude light to prevent greening.
Common issues
Late blight (Phytophthora infestans): use resistant varieties, wide spacing, morning watering, remove infected foliage promptly. Early blight: maintain soil health, rotate, and remove lower leaves if crowded. Common scab: keep pH 5.0–6.0, avoid fresh manure and drought during tuber initiation. Wireworms and slugs: trap and hand-pick; avoid following fresh sod. Aphids and virus: plant certified seed, control volunteers. Colorado potato beetle: hand-pick eggs/larvae; encourage predators; use row cover early.
Rotation schedule
Rotate on a 3–4 year cycle away from Solanaceae (potato, tomato, pepper, eggplant). Follow potatoes with legumes or cover crops to rebuild nutrients. Avoid planting after grassy sod or fields with known wireworm pressure; if unavoidable, grow a year of non-host cover crops first.
Pollination
Not required for tuber production; flowers are self-fertile but often irrelevant when growing from seed tubers.
Companion plants
Beans (bush), corn, calendula, marigold, nasturtium, chamomile, chives, horseradish (row ends). Green manures like buckwheat or clover before planting.
Incompatible plants
Tomato, pepper, eggplant, and other nightshades (shared pests/diseases); avoid following root crops prone to wireworm. Keep away from raspberries if possible (harbor blight).
