Guy Barter shares the secrets of this popular tuber
Potatoes have been grown for 7,000- 10,000 years, starting out in South America in present day Peru and Bolivia and gradually becoming an increasingly important global crop being rich in energy and minerals and useful levels of vitamin C and some high quality protein. According to FAO, global production in 2014 was 381,682,144 tonnes of which 5,911,000 tonnes was grown in the UK (excluding garden crops). In global terms it is the fifth most important food crop behind sugar cane, maize, paddy rice and wheat and ahead of soya beans, and third in the UK behind wheat, barley and sugar beet and ahead of oilseed rape.
Consumption of fresh potatoes has fallen in the UK and not only do we eat less, almost half are processed as crisps, oven chips and other products. In 1961 more potatoes were produced than any other crop in the UK (6,811,000 tonnes).
In contrast garden potatoes seem as popular as ever with great interest in this nutritious and easy-to-grow crop, but perhaps in different ways with current interest high in salad and ‘heirloom’ types of potatoes.
Cultivation
Although potatoes can be raised from ‘true potato seed’ this is rare and almost all are grown from ‘seed’ tubers bought in the winter and stored cool until they are needed. Seed tubers are grown to be free of viruses, particularly in hill farms in Scotland where the cool climate deters the virus laden greenfly that spread disease in the lowlands.
Seed can be planted as received but there are good reasons to chit or sprout seeds; earlier crop, higher early yields and earlier maturity so crops can be gathered before blight or slugs ruin them.
Chitting is merely the placing of tubers rose end (the end with any small buds) uppermost in trays in the light in late winter and allowing sprouts to grow. A bright unheated room is ideal, neither too hot nor too dark which lead to leggy weak sprouts. Frost kills potatoes.
Once the sprouted, the ‘seed’ is ready to plant. Early potatoes are set out in March at about 30cm/1ft allowing 60cm/2ft between rows, maincrop ones in April at 35cm/14ins and 70cm/28ins respectively. The precise date determined by how far north a garden is and how prone to late frosts.
The simplest way to grow potatoes is to plant with a trowel or in a shallow trench into ground fortified with compost or manure and ideally fertiliser, too. Potatoes are capable of enormous yields but need to be well fed to do this. Allow 30-80cm of soil over the tuber at planting. As the shoots emerge draw soil from between the rows
