Growing potatoes

Chit seed potatoes from late winter, plant them in a sunny bed between late March and early May, earth them up as they grow, then lift them from June (earlies) to October (maincrops). That's the whole job. The rest of this page fills in the detail. Timings are ranges, because frost risk varies a lot from place to place and through the season.

At a glance

Difficulty	Usually easy and reliable
Plant	Late March (first earlies) to early May (maincrops)
Depth	In a trench about 15cm deep
Spacing	Earlies 30cm apart, rows 60cm apart; maincrops 37cm apart, rows 75cm apart
Harvest	June to October, depending on type
Protection and support	Earth up as they grow; cover shoots if frost is forecast
Rotation group	Potatoes and tomatoes

Figures from the RHS. The sowing calendar and plot planner use the same months and spacing.

Overview and difficulty

Potatoes are a classic first crop on a new plot, and the RHS calls them usually easy and reliable croppers. They take a fair bit of room, so decide how many rows you really want before ordering seed.

Seed potatoes come in three groups, and the group decides when you plant and when you dig:

Type	Plant	Lift
First earlies	Around late March	June and July
Second earlies	Early to mid-April	July and August
Maincrops	Mid-April to early May	Late August to October

Earlies give you new potatoes early in summer, and blight is less likely to affect them. Maincrops take longer and are the ones to store.

Conditions

Potatoes need an open, sunny site that isn't prone to late frosts, and rich, fertile soil. If your plot is in a cold or frosty spot, plant towards the later end of each range.

Space and kit

• A bed big enough for your rows at the spacings above
• Egg boxes or seed trays for chitting
• A spade or draw hoe for the trench and for earthing up
• Fleece or another cover in case of late frost

Sowing and planting

Chitting. Chitting means letting seed potatoes sprout before planting. It's most useful with early varieties. Start from late January in milder areas, or up to early March in colder ones. Stand the tubers in egg boxes or seed trays with the buds (eyes) facing up.

Planting. Dig a trench about 15cm deep and set the potatoes along the bottom with the shoots pointing up. Space earlies 30cm apart in rows 60cm apart, and maincrops 37cm apart in rows 75cm apart. Cover them over and label the row.

Routine care

• Earth up: when the shoots reach about 23cm, draw soil up around them to make a ridge, and keep going until it's 20–30cm high.
• Watch for frost: new shoots are easily hurt. If frost is forecast after they've come up, cover them.
• Water in dry weather for a good crop.

Common problems

Blight is the big one in a wet summer. The same pathogen attacks tomatoes. It's most common in warm, wet weather, and the spores blow in from other plots. If it takes hold badly, cut the stems off near soil level. There are no fungicides for gardeners to use against it. Blighted potatoes won't store. Our blight guide covers spotting it and what to do.

Soil pests and diseases build up if potatoes go in the same place every year, so move them to a new bed each year as part of a rotation.

Harvest and storage

First earlies are usually ready in June and July, second earlies in July and August, and maincrops from late August to October. Lift earlies as you need them.

Keep stored maincrops somewhere dry, cool and frost-free, such as a garage. Aim to eat them before early spring, when they start to sprout and shrivel.

Smaller spaces

No room for rows, or want a few extra earlies? Use a container at least 30cm wide and deep, with one seed potato for every 30cm of width. Earlies suit containers best, because the plants are smaller and mature faster. Potato grow bags work too, as long as you pierce drainage holes in the bottom. Stand them in full sun and keep them well watered.

FAQs

Do I have to chit potatoes?

It's most useful for earlies. Start from late January to early March, depending on where you are.

Can I plant potatoes from the supermarket?

Use certified seed potatoes if you can. VERIFY: find an RHS, GOV.UK or APHA source on why certified seed potatoes are recommended over shop-bought potatoes before keeping this answer.

When are my potatoes ready?

First earlies are usually ready in June and July, second earlies in July and August. Maincrops come from late August to October.

Related guides and your next step

Next step: pick the bed your potatoes go in this year, then order seed potatoes and set out egg boxes or trays to chit them in. The plot planner shows how many fit and where they sit in your rotation.

• Potato and tomato blight
• Crop rotation: a simple 4-year plan
• What to grow in your first allotment year