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How to plant seed potatoes in the UK

Updated: October 2026

The tubers are in a bag on the table, and the listing did not give you a date. First and second earlies want a few weeks of short shoots before they go into a trench. Maincrops gain little from that wait. Plant once you can cover a frost, at the Royal Horticultural Society spacings, and earth up so the new potatoes stay in the dark. This is the spring method. The packs are on our [seed potatoes](/hub/root-vegetables/seed-potatoes) comparison. We did not run a plot trial. Shelf prices move, and a qualifying purchase can earn us a commission at no extra cost to you.

The tubers are in a bag on the table, and the listing did not give you a date. First and second earlies want a few weeks of short shoots before they go into a trench. Maincrops gain little from that wait.

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On this page
  1. 1.Chit earlies, and skip the fuss for maincrops
  2. 2.Planting depth and spacing
  3. 3.Frost and earthing up
  4. 4.When the tubers were already soft

Chit earlies, and skip the fuss for maincrops

Chitting lets short shoots form before planting. The RHS says it is worthwhile for first and second earlies, and of little point for maincrops. Start earlies about four to six weeks ahead, in a cool, light, frost-free place, eyes upwards. A warm, dark cupboard is the wrong room. Gardens Illustrated warns that warmth and darkness make long, brittle shoots. The RHS spring notes put a useful shoot at about 3 cm. On earlies, rub the cluster back to about four shoots. A seller line that says plant in January for a May harvest, as on the Arran Pilot listing, is earlier than the calendar below. If the shoots are already long and pale, the room was too warm. Crop class is on first early versus maincrop.

Planting depth and spacing

The RHS default is a trench about 15 cm deep. Set earlies about 30 cm apart, with about 60 cm between rows. Set maincrops about 37 cm apart, with about 75 cm between rows. Those gaps leave room to earth up later. Lay the tuber shoots upwards, cover it, and mark the row. Keep an early and a maincrop in separate rows so you do not dig the storing crop when you lift the new potatoes. The RHS puts first earlies in around late March, second earlies from early to mid-April, and maincrops from mid-April to early May. Wait if the soil is cold and wet. SRUC’s Dandelion guide holds planting until heavy frosts have passed, from about mid-April on a warmer west-coast site to early June on high ground. This page keeps the RHS months.
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Frost and earthing up

Young shoots are vulnerable in April and May. On a frost night the RHS says cover them with a cloche, hessian, straw, fleece or soil. Heavier fleece is about 2°C of protection, enough for a light frost and not for a hard one. A blackened shoot often regrows from below ground. A frosted shoot is not a reason to call a professional. Earth up when the shoots are about 23 cm tall, and leave about 10 cm of leaf in the light. The RHS says the mound is not mainly a yield trick. It keeps developing tubers out of the sun. The Food Standards Agency says cut green parts away and reject the potato if the rest still tastes bitter. The RHS calls green tubers poisonous. A patio bag is on seed potatoes in containers.

When the tubers were already soft

Soft seed is bad stock, not a date you can prune your way out of. Swift reviews in this set describe tubers that went soft while chitting, packs with no eyes, and very small seed. If the tuber is soft, split or eyeless on arrival, planting it spends the row on a potato that was already failing. There is no rescue soak or deeper hole on this page, because the sources do not give one that turns old stock into sound seed. Photograph the bag, tell the seller, and plant only firm, eyed tubers. The checks sit on the seed potatoes buying guide.

Common questions

Do I have to chit maincrop potatoes?
No. The RHS says chitting helps first and second earlies, and is of little point for maincrops. Earlies want about four to six weeks in a cool, light, frost-free place from late January in milder areas. Maincrops can go in from mid-April to early May, later if the site is cold, without that wait.
How deep and how far apart should I plant?
The RHS trench is about 15 cm deep. Earlies go about 30 cm apart, with rows about 60 cm apart. Maincrops go about 37 cm apart, with rows about 75 cm apart, shoots upwards. A colder, higher garden waits until heavy frosts have passed. A seller’s plant in January line is not this calendar.
What if frost is forecast after the shoots appear?
Cover them. The RHS lists a cloche, hessian, straw, fleece or soil for frost nights in April and May. Heavier fleece gives about 2°C of protection. A shoot that blacks off often regrows from the tuber. A frosted shoot is ordinary spring weather, not a quarantine case.
Why earth up if it does not raise the yield?
The mound keeps tubers in the dark. The RHS says earthing up is not mainly a way to get a heavier crop. Draw soil up when shoots are about 23 cm tall, and leave about 10 cm of leaf. The RHS calls green tubers poisonous. Do not treat a green potato as a harmless extra you can scrub and eat.
What if the tubers go soft while chitting?
Treat that as bad stock. Swift reviews describe seed that softened while chitting, and Christmas-mix reviews include rot and tubers with no eyes. Do not invent a soak or a deeper hole. Plant the firm, eyed tubers only.
Can I use these steps for a Christmas crop?
Not the spring dates. The RHS festive method uses cold-stored earlies in July or early August in a frost-free greenhouse, or late August to early September under cover, and it skips chitting because the soil is warm. Outdoor autumn crops face blight. This page does not add a second set of spacings.

Related pages

Seed potatoes

Best seed potatoes for chips, salads or mixed bags

Buy certified seed potatoes: labels, counts and risk

Growing potatoes in containers: pots, bags and drainage

First early vs maincrop potatoes: date, space and blight

Sources

Public UK sources, checked with the amazon.co.uk listings of 15 October 2026. Shelf prices and star lines are the figures in the display file. This page did not visit a garden centre.

  1. GOV.UK: Seed Potato Classification Scheme (retrieved 15 October 2026)
  2. Seed Potatoes (England) Regulations 2015 (retrieved 15 October 2026)
  3. SASA: Seed and ware potatoes classification (retrieved 15 October 2026)
  4. DAERA: Seed potatoes (retrieved 15 October 2026)
  5. GOV.UK: Farm-saved seed (retrieved 15 October 2026)
  6. RHS: How to grow potatoes (retrieved 15 October 2026)
  7. RHS: Potato blight (retrieved 15 October 2026)
  8. Potato Council: Growing healthy seed potatoes (retrieved 15 October 2026)