How to Grow Potatoes at Home: Chitting & Earthing Up

How to Grow Potatoes at Home: Chitting & Earthing Up

Try Growli: Snap a photo of your sprouting seed potatoes or yellowing foliage and the Growli app will tell you exactly when to chit, earth up, and lift your crop for your local frost dates.

Potatoes are one of the most rewarding crops for a first-time grower: a single seed potato can return several kilos of food, and the techniques that matter most — chitting, earthing up, and even watering — are simple once you know the reasons behind them. This guide draws on a documented first-year UK garden that weighed every harvest, anchored to Royal Horticultural Society (RHS) and university Extension guidance.

What seed potatoes should I buy?

Choose certified seed potatoes — not supermarket spuds — and match the variety to how you cook. Certified seed is grown to be virus-free, which matters because potatoes are prone to soilborne and viral problems. Two reliable home varieties are Maris Piper, a floury maincrop that fluffs up for roast potatoes and chips, and Charlotte, a waxy second-early that holds its shape when boiled and holds an RHS Award of Garden Merit. Floury types break down when cooked; waxy types stay firm — pick the texture you actually eat.

Varieties are grouped by how quickly they crop: first earlies (new potatoes, roughly 10 weeks), second earlies (around 13 weeks), and maincrop (around 20 weeks). Earlies dodge much of the late-summer blight pressure, which makes them a forgiving first crop.

What is chitting and do I need to do it?

Chitting means pre-sprouting seed potatoes indoors so they get a head start when planted. Stand the tubers eyes-up — the end with the most dormant buds — in an empty egg box or seed tray on a cool, bright, frost-free windowsill. According to the RHS, leave them for about 4–6 weeks until short green-purple shoots roughly 2–3 cm (about 1 in, ideally up to 5 cm / 2 in) appear, then plant out.

Chitting is most worthwhile for early varieties and gives an earlier crop, but it is not strictly essential — the RHS notes unchitted potatoes still grow perfectly well, they just crop a few weeks later. A bright windowsill matters: in the dark, shoots grow long, pale, and weak.

Should I rub off the sprouts?

Yes — keep only the 1–2 strongest sprouts per tuber and rub the rest off. A seed potato that has thrown out a dozen thin shoots is spreading its energy too thinly. Removing the weak ones channels the plant's reserves into a few vigorous stems, which generally produces fewer but larger tubers. Rub them off gently with your thumb before planting.

There is also a trick to stretch your seed potatoes further: if a tuber has several strong sprouts spread across it, you can cut it in two so each half carries at least one healthy eye. Let the cut surface dry and callus for a day or two before planting to reduce rotting. In the documented UK garden, one well-sprouted tuber this way produced two productive plants — a simple way to roughly double your plant count from the same bag of seed.

Where should I plant potatoes?

Plant in full sun, in loose, fertile soil, and well away from thirsty trees. Dig a trench about 15 cm (6 in) deep and set tubers sprout-side up. The RHS spacing guide:

Keep potatoes away from large, water-hungry trees such as birch. Tree roots draw most of the available moisture from the surrounding soil, and that drought stress tends to produce small tubers — and, as we'll see, more scab. Potatoes also grow well in deep containers, sacks, or raised beds, which is handy if your only sunny spot is paved. If you're filling a deep bed for them, our guide on the best soil for raised vegetable beds covers the right mix.

How does earthing up work?

Earthing up means drawing soil up around the stems as the plants grow — it builds more tubers and keeps them in the dark. Potatoes form along the buried portion of the stem, not from the roots, so the more stem you cover, the more room the plant has to set tubers. The RHS suggests starting once shoots reach about 23 cm (9 in) tall: draw soil up into a ridge, leaving the top 10 cm (4 in) of growth showing, and repeat several times through the season until the ridge is 20–30 cm (8–12 in) high.

Earthing up does a second, safety-critical job. Tubers that push to the surface and get hit by light turn green and produce solanine, a naturally bitter, mildly toxic compound. The RHS is blunt about this: discard any potatoes that have gone green, as they're potentially poisonous. Keeping them buried in darkness is the whole point.

How often should I water potatoes?

Water deeply and consistently, especially once tubers begin to form — uneven moisture is the main avoidable problem. During dry spells, give the bed a thorough soak at the base rather than light daily sprinkles, which only wet the surface. Container-grown potatoes dry out fast and need the most attention. For a full routine, see how to water a vegetable garden — the same deep, base-only, morning approach applies.

Consistent watering matters because it directly controls scab, covered next.

What causes potato scab and is it still safe to eat?

Potato scab is caused by a soilborne microbe and encouraged by dry soil during tuber development — and scabbed potatoes are still safe to eat after peeling. The rough, corky brown patches you sometimes see are common scab, caused by Streptomyces bacteria. University of Maine Cooperative Extension notes that dry soil conditions while tubers are setting "reduce competition and can serve to encourage infection," which is why keeping the soil evenly moist during tuber formation is the single best home defence.

Crucially, scab is a cosmetic blemish. Extension sources describe it as affecting grade quality, with only a negligible effect on total yield or storability — the potatoes underneath are perfectly edible once the affected skin is peeled away. (This is different from green tubers, which should always be discarded.) Avoid adding lime before planting, since the scab microbe favours neutral-to-alkaline soil, and don't plant near moisture-stealing trees.

When and how do I harvest and store potatoes?

Harvest first earlies about 10 weeks after planting when the plants flower; lift maincrop when the foliage yellows and dies back. For new potatoes, the RHS advises lifting once the flowers are open or the buds drop — the tubers will be about hen's-egg size. Maincrop varieties are usually ready around 20 weeks, when the leaves turn yellow and collapse; you can leave them in the ground a little longer to bulk up.

Lift gently with a fork from the outside of the ridge to avoid spearing tubers. Earlies are best eaten fresh, while maincrop potatoes store for months in paper or hessian sacks somewhere cool, dark, and dry — light triggers greening even after harvest. In the documented UK garden, a small bed returned roughly 4 kg of Charlotte and 5 kg of Maris Piper, broadly in line with the 8–10 tubers per plant many home growers report, though your yield will vary with variety, soil, and season.

For a wider crop plan and bed setup, start with our vegetable garden guide for beginners, and keep slugs and other pests in check with organic pest control for the vegetable garden.

About the sources

This guide is built on a documented first-year UK garden (Alex) that weighed each harvest — including Charlotte and Maris Piper crops — presented as a real-world journey for context, not horticultural authority. Specific claims on chitting, spacing, earthing up, harvest timing, and green-tuber safety are anchored to RHS guidance, and the scab-and-soil-moisture link to University of Maine Cooperative Extension.