Potato

Quick facts

Category

roots bulbs

Difficulty

beginner

Days to harvest

70 to 130 days

Harvest type

single harvest then replant

Spacing

30 cm between plants

Environment

Temperature

10–25°C

pH

5 to 6.5

EC (hydroponic)

1.8 to 2.4 mS/cm

Daily light

18 to 28 mol/m²/day

Climate and zones

USDA zones

2 to 11 (winter low around -46°C or warmer)

Frost tolerance

frost hardy (handles regular frost)

Season

cool (spring and fall crops)

Viable growing environments:

• outdoor year-round (in zone)
• outdoor in growing season (annual)
• unheated greenhouse / hoop house
• heated greenhouse

USDA zone bounds reflect outdoor year-round survival. Anywhere outside the bounded zone range, this crop still grows as an annual in the warm months (outdoor_seasonal), under cover (greenhouse), or indoors under lights.

Growing systems

Potato works in:

• soil bed
• media bed (ebb and flow)

Root mass is very heavy - thin-channel systems (NFT, vertical towers) can't hold this crop mechanically, hence the system list above.

Growing media

The substrate the roots sit in. Choice depends on the system (clay pebbles don't fit NFT channels; rockwool isn't used in media beds) and the crop (potato works in the media listed below).

Bacterial surface area matters for aquaponics: clay pebbles, lava rock, and pumice double as biofilter substrate. Low-surface media (rockwool, perlite, pea gravel) work in hydroponics but need a separate biofilter in aquaponics.

Nutrient demand by stage

NPK ratios are relative weights at each growth stage; the nutrient mix calculator scales them to absolute grams or ml. EC targets shift through the plant's life: seedlings need a much lighter solution than fruiting adults.

Companion-growing notes

• Heavy uptake of potassium. Co-grown crops with the same demand will end up deficient even at "correct" EC. Plan around this in shared reservoirs.

Aquaponics suitability

Compatible with typical aquaponics nutrient profiles. Fish waste provides enough nitrogen for healthy growth; supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.

Care notes

Feasible in deep media beds or large containers (30 L) with loose substrate that allows hilling. Not suited to NFT, DWC, or other water-culture systems. EC 2.0-3.0 mS/cm. pH 5.0-6.5 (prefers slightly acidic conditions; above pH 7.0, common scab disease increases). Temperature: 15–22°C for tuber formation (critical: above 28°C, tuber formation slows or stops). Moderate to high light (DLI 14-22 mol/m2/day). Plant seed potatoes (small whole tubers or cut sections with 2-3 eyes each) 10–15 cm deep. As the plant grows, mound additional media around the stem (hilling) to keep developing tubers in darkness. Harvest 'new' potatoes (small, thin-skinned) 60-70 days after planting, or full-sized tubers at 90-120 days when the foliage dies back. Cure harvested tubers in a dark, cool (10–15°C), humid location for 1-2 weeks before storage. Late blight (Phytophthora infestans, the disease that caused the Irish famine) is the most serious disease; resistant varieties and avoiding wet foliage reduce risk. For aquaponics media beds, potatoes grow well but need deep, hilling-friendly substrate.

Notable varieties

A starting shortlist of cultivars worth knowing about. Not exhaustive: the seed catalogs list hundreds of named varieties. These are the ones home growers commonly choose between.

Further reading

• Best crops for hydroponic beginners
• The Kratky method: grow lettuce with zero electricity