Explore Vegetables.im
Potatoes.vegetables.im
Sources

Where the facts come from

Every factual claim on this site links to its source. This is the full list.

How we checked

Each fact was written alongside its source. Our build script stores the source text and, for every fact, checks that the key words and figures really appear in it. 101 of 101 checks passed when this site was last built (checked 29 Oct 2026). Where we couldn’t read a source, we left the claim out. We quote short phrases only, and never reproduce anyone else’s images.

Figures that change

Pest status, recommended variety lists, forecasting services, records and event dates can change. Facts like these are marked “checked 29 Oct 2026”.

What we leave out

This is a site about growing potatoes and their history. We don’t give health, nutrition or diet advice, even where a source does. We don’t recommend pesticides or other chemicals. Our drawings are not identification guides: for a diagnosis, use the RHS pages linked here. Where sources disagree, we show both rather than choose silently.

Royal Horticultural Society (RHS) (5)

Garden Organic (3)

National Allotment Society (2)

GOV.UK (2)

Royal Botanic Gardens, Kew (3)

International Potato Center and the UN (2)

Encyclopaedia Britannica (2)

When sources disagree

Where sources give different figures, we show all of them, with links, and say how we handle it.

How far apart?

How we handle it: The RHS gives earlies 30cm apart in rows 60cm apart, and maincrops 37cm apart in rows 75cm apart. Garden Organic gives earlies 30cm in rows 50 to 60cm, and maincrops 40cm in rows 70cm. Both are shown in the calendar table and the planner.

When to plant?

  • RHS planting times: first earlies around late March, second earlies early to mid-April, maincrops mid-April to early May. Plant a little later in colder regions. RHS: How to grow potatoes
  • Garden Organic planting times: earlies mid- to late March, second earlies early to mid-April, maincrops mid- to late April. Garden Organic: Potatoes growing guide
  • Garden Organic says the soil should be at least 6C (43F) at planting. A good sign is when grass and weeds begin to grow. Garden Organic: Potatoes growing guide

How we handle it: The RHS and Garden Organic agree on second earlies (early to mid-April) and differ slightly on first earlies and maincrops. We show both, and Garden Organic’s soil-temperature sign (at least 6C) as a better guide than the calendar alone.

When to start earthing up?

  • RHS: when shoots are about 23cm (9in) tall, draw soil up to form a ridge, leaving the top 10cm showing. Repeat a few weeks apart, to a final ridge of 20–30cm. RHS: How to grow potatoes
  • Garden Organic: earth up first when plants are around 15cm tall, leaving about 5cm showing, and again just before the foliage meets across the rows. Garden Organic: Potatoes growing guide

How we handle it: The RHS says start when shoots are about 23cm tall, leaving 10cm showing; Garden Organic says about 15cm tall, leaving about 5cm. We show both.

How long do earlies take?

How we handle it: Figures run from nine to ten weeks (Garden Organic’s growing guide) to around 12 weeks for first earlies (RHS and Kew), and 10 to 12 weeks in containers. Varieties, weather and where you grow all make a difference, so we quote each with its source.

How long should the shoots be before planting?

How we handle it: The RHS mentions sprouts about 5cm long; Garden Organic says plant when shoots are 2cm. Both say the process takes four to six weeks.

How long to wait before lifting maincrops for storing?

  • To store maincrops, wait until the leaves turn yellow, cut off the top growth, wait 10 days, then dig up the tubers and dry them in the sun for a few hours. RHS: How to grow potatoes
  • Garden Organic: maincrops store best if left in the ground for two to three weeks after the haulms (stalks) have died back. Garden Organic: Potatoes growing guide

How we handle it: The RHS says cut off the top growth once the leaves yellow and lift 10 days later; Garden Organic says leave them two to three weeks after the haulms have died back. Both aim to let the skins set before storing.

How many potato varieties are there?

How we handle it: The International Potato Center’s own page gives both “over 4,000 edible varieties” and “more than 4,500 varieties of native potatoes”. One Kew page says over 5,000 varieties; another says over 100 types (probably meaning ones commonly grown). We don’t pick one number.

How long ago were potatoes first grown?

How we handle it: Britannica says domesticated over 7,000 years ago; Kew says the modern potato was cultivated around 8,500 years ago in what is now southern Peru. The two don’t clash (8,500 is more than 7,000), but they aren’t the same figure, so we give both.