Growing potatoes through the mild Spanish season

Potatoes, Solanum tuberosum, came to Europe through Spain in the sixteenth century from the Andes of Peru and Bolivia, so Spain has grown them for a very long time. On the Costa Blanca the trick is to fit the crop into the mild months and keep it out of the summer, when hot soil stops the plants forming tubers.

Two planting windows

Mild coastal gardens often use two planting windows. A late-winter crop can go in from late January to March for lifting before the strongest heat. A second crop can be planted as summer eases for an autumn or early-winter harvest. These are guides, not fixed dates: wait until frost risk is acceptable, avoid planting into hot soil and choose an early cultivar that fits the available weeks.

Seed potatoes and chitting

Buy certified seed potatoes rather than planting supermarket tubers, which may carry disease and are often treated to suppress sprouting. Early and second-early varieties suit the short Costa Blanca seasons better than maincrop types. Stand the tubers in a light, cool, frost-free place for a few weeks before planting so they form short green sprouts.

Ground, containers and sacks

Plant tubers about 12 to 15 centimetres deep and 30 centimetres apart, in rows 60 centimetres apart, in soil improved with compost. As the shoots grow, draw soil up around the stems in stages. This earthing up gives the plant more room to form tubers and stops light reaching them, which turns exposed tubers green and inedible.

On thin or stony ground, large containers, tubs or purpose-made potato sacks work well and make harvesting simple. Use three or four seed potatoes to a 40-litre container of loam-based compost and keep it consistently watered.

Water

Water is often the limiting factor here. Keep the soil steadily moist as the canopy develops and the tubers bulk, then taper off as the foliage begins to yellow before harvest. Erratic watering can contribute to misshapen or split tubers.

Pests and problems

Late blight can appear in a wet spell, while potato tuber moth is favoured by warm conditions and its larvae tunnel into exposed tubers. Keep tubers well covered, do not leave them lying in the plot after harvest and clear volunteers and debris. The quarantined Guatemalan potato moth is subject to Spain's national control programme and has affected the Canary Islands, Galicia and Asturias. Follow current plant-health restrictions and never move seed potatoes out of a regulated zone. Wireworm damages tubers on recently grassed ground. Common scab, raised corky patches on the skin, is worse on dry alkaline soil and does not affect eating quality.

Harvest and storage

Lift earlies as needed once the plants flower. For storage crops, cut the foliage and leave the tubers in the ground for a week or two to firm the skins, then lift on a dry day. Store somewhere cool, dark and airy. Warm storage brings sprouting and, with tuber moth present, continued damage in the store.

Sources and review

This guide was reviewed in September 2026 using the Kew Plants of the World Online record for Solanum tuberosum, the Royal Horticultural Society potato guide and the Spanish agriculture ministry's current national information and control programme for Tecia solanivora.