How to plant potatoes: a practical guide from seed to harvest

Seed potatoes are tubers grown and certified specifically for further planting. They are inspected for health status, carry a known variety and come with documentation of origin and multiplication class.

Regular table potatoes from a shop do not go through this process. They can carry viruses or bacterial diseases, you may not know the variety or age, and the field result is unpredictable. For commercial production, table potatoes are not used as seed.

Healthy certified seed is one of the basic prerequisites for an even stand, yield and quality. Some diseases and harmful organisms can burden the plot for further seasons.

Variety choice sits on three axes: earliness (very early, early, mid, late), intended use (early table, table cooking type, fries and crisps, starch, organic) and local conditions (soil type, rainfall, irrigation, disease pressure).

The cooking type (A, B, C) is chosen according to the intended culinary use; fries call for a variety with matching dry matter and shape, starch factories for a variety selected on starch yield. Organic programmes weigh a combination of traits — resistance, earliness and fit with local conditions.

The signal to plant is soil condition, not a calendar date. As an indicative guide, the soil should be warmed to around 8 °C at planting depth, dry enough to work well and free of compaction. In most parts of the Czech Republic this typically falls between the second half of April and early May; earlier in warmer regions, later at higher altitudes.

Planting into cold, wet soil is a common mistake — tubers emerge slowly, rot more easily and the crop starts at a disadvantage. Also watch for late frosts; young foliage is easily damaged.

Pre-sprouting is optional but often useful for early varieties and smaller acreages. It can support faster and more even emergence, particularly for early production.

Spread the seed in a single layer in boxes or crates in a light place at roughly 10–15 °C. After a few weeks short, thick, dark green sprouts form. Long white sprouts grown in the dark are not desirable — they break easily. Plant pre-sprouted tubers gently so the sprouts stay intact.

Plant healthy, undamaged whole tubers. Cutting large tubers is not a standard professional practice — it increases infection risk and is not recommended as routine.

Working reference spacings: planting depth 8–12 cm, 30–35 cm within the row, 60–75 cm between rows. These values are indicative; the actual spacing and depth are set by variety, seed size, soil and technology (manual planting, standard planters, ridging planters, drip-irrigation systems).

Through the season three things matter most: ridging, weeds and even moisture. Ridge progressively until the canopy closes — it protects tubers from light and greening. Weeds are best managed mechanically or agronomically; they compete hard with young plants.

Moisture should be even — the soil should not dry out completely and it should not be waterlogged; waterlogging feeds rots. Watch the canopy and leaves for signs of disease and pests (late blight, Colorado beetle, viruses).

Plant protection follows current authorisations, the product label and expert advice for your region and variety. Universal recommendations to "use a fungicide" or "spray a pesticide" do not apply — the right approach is always specific.

Early potatoes are lifted progressively once they reach a marketable size. Table and processing varieties are harvested after the haulm has died down, when skin is set and tubers are physiologically mature — this greatly reduces mechanical damage during harvest and handling.

Harvest in dry conditions into dry soil. Wet tubers store poorly. Minimise drops, hard impacts and rough handling; every bruise is a gateway for storage rots.

Only healthy, dry, clean and undamaged tubers go into store. Discard damaged or infected tubers at harvest and grading.

The store should be dark, cool, ventilated and at stable humidity. The exact temperature depends on the purpose — table potatoes for fresh use, potatoes for fries or crisps and seed all store differently. There is no single universal temperature that fits every purpose.

Check the store regularly so a local problem does not spread to the whole batch.