Potatoes are grown from specially prepared ‘seed’ potatoes (or tubers). These are just like potatoes you buy from the supermarket, but they’re certified virus-free. You can buy seed potatoes from late winter onwards. You then start them off indoors by letting them sprout, before they are planted.
Preparation before planting
It’s important with earlies, and a good idea with maincrops, to ‘chit’ the seed potatoes before planting. This means allowing them to start sprouting shoots.
Stand them rose end up (the end with the most small dents, or eyes) in egg boxes or trays in a light, frost-free place. The potatoes are ready to plant when the shoots are about 3cm (1in) long. With early potatoes, rub off the weakest shoots, leaving four per tuber.
Potato plants need ‘earthing up’ as they grow, to protect early shoots from frost damage and ensure the developing potatoes aren’t exposed to light, which turns them green and poisonous.
It’s a simple process – once the stems are about 23cm (9in) tall, draw soil up around them, creating a ridge about 15cm (6in) high. As the stems grow, repeat the process several times. The final height of the ridge should be 20–30cm (8in–1ft).
Keep the plants well watered in dry weather – particularly once the tubers start to form. Maincrop potatoes benefit from a nitrogen-rich fertiliser around the time of the second earthing up.
Planting time varies, depending on the type of potato you’re growing:
First earlies – around late March
Second earlies – early to mid-April
Maincrops – mid- to late April
The timing also depends on where you are in the country – planting should be slightly later in colder regions and can be earlier in milder ones. And when growing in containers, you can plant earlier too.
Potatoes need a sunny site. Avoid planting in a spot prone to late frosts, as the newly emerging foliage is susceptible to frost damage in April and May.
Prepare the ground, ideally the previous autumn or winter, by digging in plenty of organic matter such as garden compost or well-rotted manure.
The traditional planting method is to dig a narrow trench 12cm (5in) deep. Space the tubers 30cm (1ft) apart for earlies and 37cm (15in) for maincrops, in rows 60cm (2ft) apart for earlies and 75cm (30in) apart for maincrops. Apply a general-purpose fertiliser at this stage.
How to plant early potatoes
Gardener, blogger and allotmenteer Bryony Willis, shows you how to plant early potatoes.
Other planting methods
Potatoes can also be grown under black polythene sheets. The tubers are planted through slits in the polythene. The advantages of this method are that there is no need to earth up, and new potatoes form just below the surface, so there’s little or no need to dig.
Small crops of potatoes can also be grown in large, deep containers. This is a good way to get an early batch of new potatoes. Fill the bottom 15cm (6in) of the container with potting compost and plant one seed potato just below this. As the new stems start growing, keep adding compost until the container is full.
This is a common disease in wet, warm summers. The initial symptoms are a rapidly spreading brown watery rot, affecting leaves, and stems. Tubers can be affected too, and have a reddish-brown decay below the skin, firm at first but soon developing into a soft rot.
Unfortunately once blight starts, it is very difficult to stop. You can remove blight-affected leaves, but removing too many leaves will damage the plant’s ability to grow. Earthing up potatoes provides some protection to tubers. Try blight resistant cultivars or stick to earlies which are usually harvested before blight strikes.
More info on Potato blight
Potato blackleg is a common bacterial disease which causes black rotting at the stem base. Initial infections cause stunted growth and yellowing stems. If tubers form, the flesh may be grey or brown and rotten.
Remove and destroy infected plants. Rotate crops. Buy resistant varieties such as 'Charlotte', 'Pixie' and 'Saxon'.
More info on Potato blackleg
This disease causes raised scab-like lesions on the potato surface. It does not affect the taste of the potato, and is easily removed on peeling.
There is no control for scab, and you usually won’t know anything is wrong until harvest time. Scab can be worse in dry weather, so keep potatoes well watered. Don’t store any potatoes with scab.
More info on Potato scab
Potato tuber rots are a frequent cause of losses prior to, or after, lifting. Significant problems often follow a wet growing season, particularly if the tubers are then lifted from wet soil.
Use good quality, resistant certified seed tubers when planting and harvest when the soil is neither wet nor very hard and dry. Store in cool, dry conditions.
More info on Potato rot
First early potatoes should be ready to lift in June and July
Second earlies in July and August
Maincrops from late August through to October
With earlies, wait until the flowers open or the buds drop. The tubers are ready to harvest when they’re the size of hens’ eggs.
With maincrops for storage, wait until the foliage turns yellow, then cut it down and remove it. Wait for 10 days before harvesting the tubers, and leave them to dry for a few hours before storing.
Nigel Slater suggests roasting young potatoes – although this may sound like an odd thing to do, it brings out their fudgy texture and crisp, papery skins.
Multi-purpose first early with smooth, white skin and shallow eyes and white/creamy flesh. Will chip, bake or boil. Potential showbench variety.
A very popular second early salad variety. Produces lovely pear shaped, yellow skinned tubers. Excellent either hot or cold.
Recommended Potatoes — first earlies
Introduced over 60 years ago, high yielding first early, waxy flesh when cropped young.Some slug resistance.
'Maris Bard' AGM
Very early cropping first early. White round tubers, white flesh with good drought and common scab resistance. Good "new potato" flavour.
One of the earliest to crop first early varieties. Can be cropped 8/10 weeks after planting in ideal growing conditions. Good for container growing. Round, white skinned, white fleshed tubers.
First early salad potato. Distict nutty flavour with firm waxy flesh. Oval, meduium sized tubers, with shallow eyes and yellow flesh.
Recommended Potatoes — second earlies
The most popular second early variety for exhibition over many years. White oval tubers with purple splashes around the eyes. Consistant size and colour. Many uses and good disease resistance. Top Class!
Second early,white skinned, cream fleshed, short oval tubers. World record yields when well grown. Showbench variety.
Recommended Potatoes — maincrop
'Maris Piper' AGM
Most widely grown maincrop potato in the UK. Introduced in 1966, and bred to resist potato cyst nematodes.White skinned, white fleshed round tubers which store well.
'Sarpo Mira' AGM
Launched in 2002, late maincrop, as one of the highest resistant varieties to potato late blight and good slug reistance. Red skinned white fleshed oval tubers. Good for all uses and stores well.
A firm favourite with rosy skin and pale yellow flesh. This is a versatile maincrop potato.
Recommended Potatoes — salad
'Pink Fir Apple' AGM
Late maincrop salad variety with pink skin and cream waxy flesh. Long knobbly tubers. Introduced in 1850's from France. Very distinctive nutty flavour.
Early maincrop salad potato.White skins and firm waxy yellow flesh.Long oval tubers.
Recommended Potatoes — for containers
Second early. recently introduced variety. Small oval tubers, but lots of them per root! Ready 14 weeks after planting. Good in containers.
'Sharpe's Express' AGM
First early heirloom variety, introduced in 1900. Oval tubers with white skin and lemon coloured flesh. Good "new potato" flavour.