How to grow
Potatoes

We go to great lengths at Marshalls to make sure our seed potatoes are of the finest quality, giving you the best possible chance of a great harvest. We'd go as far as to say the hardest part about growing potatoes is deciding which varieties to try! After that, the process of planting, caring for and harvesting is relatively straight-forward... but if you do need a helping hand, carry on reading!

Potatoes are grown from small seed potatoes, often called tubers. These are small potatoes that often have ‘eyes’ – the place from which their stems grow under the soil. Always buy tubers that have been certified as being free from disease.

There are four main types of seed potatoes:

• Salad potatoes are firm, with waxy flesh and a unique flavour.
• First early potatoes are the first to be ready in the year and are often known as new potatoes.
• Second earlies follow first earlies and are usually ready for harvest from early June.
• Main crop can be lifted from September to October or November and stored for up to three months in cool sacks.

• Salad potatoes can be planted in March or April.
• Plant first earlies around late March or in April. In warmer areas they can go in as early as February.
• Second earlies can go into the soil in April.
• Main crops should be planted any time from mid-April to May.

‘Chitting’ seed potatoes before you plant will help get them off to a flying start. Simply place the tubers in a cool, light place to encourage them to produce shoots.

This process is recommended for first earlies, along with second earlies and salad varieties, but not so much for main crop potatoes.

• Place the seed potatoes in a seed tray, so that they are just touching, or in sections of egg boxes.
• Keep the ‘rose end’, where most of the eyes are, at the top – this is where the chits will form.
• Place the trays or boxes in a cool, light and frost-free environment at around 7°C.
• The aim of chitting is to form plump, dark green or purple shoots about 2.5cm (1inch) long
• Thin and long white shoots are a sign of too much heat and not enough light.
• If shoots are slow to appear, move them to a warmer place about three weeks before they’re due to be planted and leave them there for a couple of weeks, before returning them to a cool spot for the final week.

Potatoes grow in most soil types but do especially well in a well-drained loam that’s not too heavy.

Ideally, prepare the ground during late autumn or early winter so that the frosts can break down the soil and dig in plenty of well-rotted organic matter, such as compost or manure, to create a reasonable depth. Avoid planting potatoes on ground that’s previously been used for this crop within the past three or four years to avoid the build-ups of pests, such as wire worm, and diseases.

Dig a v-shaped trench, or use a trowel to make individual deep holes, and place the potatoes inside. Rows running north to south will allow the sun’s rays to warm both sides of the crop.

• First and second early and salad potatoes should be planted 30cm (1ft) apart to a depth of 10cm (4 inches). Rows should be 45cm (1.5ft) apart.
• Main crop seed potatoes should be spaced 40cm (16inches) apart and 10cm (4 inches) below the soil. Aim to have rows 60cm (2ft) away from each other.
• When shoots first appear through the soil, ‘earth up’ the potatoes by pulling soil over the shoots from either side to create a ridge. This will protect the plants from late frosts, stop the light from turning potatoes green and encourage more tubers to form further up the stems.
• The earthing up process can be repeated until the ridge is about 20cm (8inches) high. Feed plants with a specialist potato fertiliser each time if desired.
• Potatoes are thirsty plants need plenty of moisture while they are growing, especially around flowering time. Water them well during dry periods.

Some growers plant seed potatoes under black polythene, with slits cut for the emerging shoots, and don’t earth up.