🥔 Potato

Potatoes are among the most productive and satisfying crops you can grow, and freshly dug new potatoes taste far better than anything from a shop. They are grown from ‘seed’ potatoes, which are small tubers saved or sold for planting, and come in three groups: first earlies, second earlies and maincrops.

You can grow them in open ground, raised beds, large pots, sacks or bags, making them suitable for gardens of almost any size. Always buy certified seed potatoes, as supermarket potatoes can carry disease and are not treated for planting.

Varieties to try

Rocket (first early, reliable)Charlotte (second early, salad)Maris Peer (second early, creamy and versatile)Sarpo Mira (maincrop, strong blight resistance)Maris Piper (maincrop, all-rounder)Pink Fir Apple (late salad, superb flavour)

From late January, stand seed potatoes in egg boxes with the end with most ‘eyes’ upwards, in a cool, bright, frost-free place. This is called chitting, and gives short, sturdy shoots that give earlier crops. Plant first earlies in mid-March to early April, second earlies in early to mid April and maincrops from mid-April to May.

Dig a trench or individual holes 10–15 cm deep, plant with the shoots upwards, space 30–40 cm apart and cover with soil. In large pots or potato bags, put 15 cm of compost in the base, plant three tubers per 30–40 cm pot, then add compost as they grow. Protect emerging shoots from frost with fleece or soil.

Top tips

• Chit seed potatoes in a bright, cool place for six weeks before planting.
• Rub off all but 3–4 of the strongest shoots for bigger potatoes.
• Cover shoots with fleece if a late frost is forecast.
• Never plant shop-bought potatoes: use certified seed.

When shoots reach 20–25 cm, ‘earth up’ by drawing soil from between the rows up around the stems, leaving just the tops showing. This stops tubers turning green and poisonous and boosts yield. Repeat every two weeks until the foliage meets across the row. Water well in dry weather, especially once the plants flower.

Potato blight, a fast-spreading disease in warm, humid weather, is the biggest threat, usually from July. Check leaves regularly for brown patches; if you see them, cut off all foliage straight away and bin it, leaving tubers in the soil for two weeks before lifting. Choosing blight-resistant varieties and growing earlies, which are lifted before blight arrives, are the best defences.

Top tips

• Earth up regularly to stop tubers turning green.
• Water deeply once plants are in flower.
• Lift earlies before blight season to dodge the disease.
• Rotate with a three- or four-year gap, as potatoes share diseases with tomatoes.

Watch out for

Potato blightSlugsPotato cyst nematodeScab and blackleg

First earlies are ready from June, when plants flower, around 10–12 weeks after planting. Lift carefully with a fork well away from the stems, and dig a test plant first. Second earlies follow from July. Lift maincrops from September, when the foliage has yellowed and died back.

For maincrops, cut off the haulm (the top growth) about two weeks before lifting so skins can set, which helps storage. Dig on a dry day and leave the tubers on the surface for a few hours to dry, then brush off the soil. Remove any damaged or slug-eaten tubers and eat them first.

Top tips

• Dig a test plant of earlies before lifting the whole row.
• Use a fork, pushing it in well away from the stems.
• Cut off maincrop foliage two weeks before lifting.
• Do not wash potatoes you plan to store.

New potatoes are best boiled with mint and tossed in butter, while salad varieties suit potato salads. Maincrops are the roasting, mashing, chipping and baking potatoes, and the waxy or floury texture of each variety decides what it does best. Never eat green or sprouting tubers, as they contain solanine, which is toxic; cut off any green patches completely.

Earlies are best eaten within days. Cure maincrops by drying them for a few hours, then store in paper or hessian sacks in a cool, dark, frost-free place at 4–10°C, where they keep for five months or more. Never store potatoes in plastic bags or in the fridge, which makes them sweet and damp. Store them away from onions.

Top tips

• Keep potatoes in the dark to stop them turning green.
• Check stored potatoes monthly and remove any rotting ones.
• Never eat green or sprouting tubers.
• Boil waxy varieties and bake or roast floury ones.