Site and soil | Varieties | Planting | Aftercare | Harvesting and storage | Pests and Diseases
Growing your own potatoes is remarkably satisfying and not all that much trouble. It is most important not to take on too much. So often, people plant too many rows and it is too much effort. Set an easily achievable target. Choose early varieties that can be eaten fresh from the soil during the summer when the ground is dry, and do not need to be stored. Early varieties suffer less from pests and diseases, usually being used before blight or slug damage becomes a problem. But there are newer varieties available too that are disease and pest resistant and make potato growing much more successful.
Site and soil
Choose an area in full open sunshine, with good air movement but not too windy or exposed either. An enclosed area tends to hold damp air which increases disease while an over-exposed garden tends to be chilled and growth is reduced.
The soil should be deep and fertile and free of perennial weeds, such as scutch grass, thistles or docks. It should have plenty of organic material but too much can lead to an increase in the slug population. Traditionally, farm yard manure was used for potatoes and garden compost can be good too, but it is usually necessary to apply some general fertiliser too at 50 to 100g per square metre.
The classic choice was the first early ‘Home Guard' followed by second early ‘British Queen', then early maincrop ‘Kerr's Pink' up to the year-end or so and ‘Golden Wonder' to store all the way to June again. All of these varieties are still good, along with other old and valued varieties, such as earlies ‘Sharpe's Express' and ‘Duke of York' and early maincrop ‘Romano', ‘King Edward' and ‘Record'. There are other varieties that have become available, recently or relatively recently, such as the earlies ‘Lady Cristl', ‘Colleen', ‘Orla', early maincrop ‘Maris Piper' and ‘Pentland Dell' and ‘Sante' and maincrop ‘Cara', ‘Rooster', ‘Druid' and ‘Valor'. Some of these show good pest and disease resistance, such as ‘Lady Cristl', ‘Orla', ‘Sante', ‘Cara', ‘Druid' and ‘Valor' as well as the very blight resistant early maincrop, ‘Sarpo Mira' and maincrop ‘Sarpo Axona'. ‘Sante' and ‘Valor' are notably eelworm resistant, carrying resistance to both kinds of eelworms.
Especially with first earlies, it is worth sprouting the potatoes before planting as this brings harvest as much as three weeks earlier. Sprouting is done by standing the tubers one-deep in shallow trays in a greenhouse or conservatory with good light. If this is done in January, the potatoes can be planted in February in mild areas to crop as early as June. This is possible in a mild garden with light soil. Later planting means later harvest but planting depends on the soil. If it is dry enough to cultivate, planting can be carried out. Very early planted potatoes run the risk of frost damage to the foliage so the earliest crops can only be grown in mild areas, or covered with horticultural fleece.
Maincrops can be planted in March, April or May. While the earlies can be planted at 30cm apart in rows spaced 50cm apart, the main crop varieties need more space, planting at 40 cm apart in rows 75cm apart. Plant first earlies by trowel, so as not to have to move much soil, but maincrop by making drills.
The basic bag of seed potatoes is 3kg and this contains about 40 potatoes, enough for about twelve to fifteen metres of row. This will yield about 20kg of early potatoes and about double that of maincrop varieties. If you choose an early variety and plant only one bag, you will not have lot of work.
Earlies can have cover with cloches or fleece against frost. Earthing up to prevent greening is likely to be necessary when potatoes are trowel-planted. To earth-up, loosen the soil along the paths between rows with a fork and then shovel it on either side to mound up around the stems when the plants are about 15cm tall.
Watering may be required for earlies and maincrop. Earlies often suffer drought in May and may need one or two heavy waterings with a sprinkler or hose. Main crop potatoes may run short of water in July or August if there is a run of dry weather.
Harvesting and storage
Earlies can be used as soon as they are large enough, although they can be very ‘soapy' at this stage. Usually when the plants have flowered or soon after, the early potatoes are ready and this can be as little as 100 days after planting in good weather or 120 days in a dull time. Maincrop varieties are usually left to build their dry matter levels to make them more floury in flavour and store better. The more dry matter the better for storage. But there may be a trade-off with blight damage to the foliage. If blight appears, it is best to take off the foliage to prevent it transferring to the tubers. If tubers are left in the ground too late in autumn, slugs will be more active as soil moist levels increase from September onwards. But this can be monitored.
Potatoes can be stored in a frost -free shed with an earthen or concrete floor, or in a pit made with straw and covered with soil outdoors. This is made by digging out a base to 10 to 15 centimetres deep in a well drained place. Straw is put in the base and potatoes piled on top. More straw is put over them and soil from the base is then placed on the straw cover. Soil from around the edges of the base is also used to pile over the straw. This leaves a trench all around the base and about 20 to 25 cm deep, acting as a drain.The straw protects from frost and the tubers are kept moist by the covering of soil.
Pests and diseases
Potatoes are prey to quite a range of pests and diseases, but the ones that cause most trouble are potato blight, slugs and eelworms. The other problems should be solved by using only Certified seed potatoes and by not growing immediately after grass. Blight can be prevented by growing blight-resistant varieties or by spraying. Slugs can be reduced by growing early varieties and varieties with some resistance such as ‘Golden Wonder' and ‘Pentland Dell'. If less organic manure is used, slug damage will not be as great and the eelworm slug-killer Nemaslug can be used - pellets are next to useless against soil-living slugs. Eelworms cause progressive weakening of the crop and are carried over as cysts in the soil. A long break of five to seven years is required to reduce damage, or choose eelworm-resistant varieties. There are two kinds of eelworm, golden and white according to the colour of the cysts in mid-summer. Both kinds can be present but usually the golden kind favours warmer parts and the white kind more northern areas.