How to grow potatoes
Potatoes are one of the most popular vegetables in the western world and have been used in Europe for over 400 years. Now they are one of the largest food crops in the world.
Potatoes take a large amount of space in your garden so plan ahead. There are two main varieties, "early cropping", or new potatoes, and "maincrop" potatoes.
Potatoes take a large amount of space in your garden so plan ahead. There are two main varieties, "early cropping", or new potatoes, and "maincrop" potatoes.
Where to grow your potatoes
Potatoes will grow in almost any type of soil but require a growing season of 90-140 frost free days depending upon the variety and prefer a well drained, fertile soil at least 2ft deep.
A warm site with some sun is ideal in the UK. Do not plant potatoes in the same place two years running as this will increase the risk of disease. It is also advisable not to plant where you have had tomatoes the previous year as they are from the same genetic family.
A warm site with some sun is ideal in the UK. Do not plant potatoes in the same place two years running as this will increase the risk of disease. It is also advisable not to plant where you have had tomatoes the previous year as they are from the same genetic family.
Soil preparation for growing potatoes
Prepare the soil for planting in late November/December. This allows the compost to be broken up by frosts over the winter and allows the soil to settle. Include plenty of organic matter at this stage.
Potatoes are tolerant of a large variety of soils but prefer a pH of 5-6. Early potatoes need a medium amount of nitrogen, maincrop require high nitrogen. A general fertilizer can be added just before planting.
Potatoes are tolerant of a large variety of soils but prefer a pH of 5-6. Early potatoes need a medium amount of nitrogen, maincrop require high nitrogen. A general fertilizer can be added just before planting.
Growing potatoes
It is better to grow varieties of potato that are recommended for your area of the country. Potatoes are grown from small tubers known as "seed potatoes". Buy these in January from your local garden centre or seed catalogues.
In northern areas the seed potatoes are "sprouted" or "chitted". Place the seed potatoes in a shallow tray, cardboard egg boxes are suitable for small amounts, with eyes/buds uppermost. Keep in a cool, frost free room with even light.
If you require a crop of large, early potatoes then leave three sprouts per plant. Rub off any remaining. The more sprouts per tuber, the higher the crop yield, but smaller potatoes.
Plant when the sprouts are up to 1 inch long. The sprouts must be green, if white then there is not enough light. In this case just remove the sprouts and leave to grow again. It is better to plant when the danger of frost is over and the soil temperature has reached about 45°f (7°C), around mid-March.
Make drills 3-6in deep and place in the tubers with sprouts uppermost covering them with at least 1in of soil. Early croppers should be planted 14in apart in rows 17in apart. Maincrop should be planted 15in apart in rows 30in apart. If possible the rows should run North-South for maximum exposure to the sun.
In cooler areas it is better to cover the plants with some protection, such as cloches, clear plastic sheeting or floating film mulch. Cut holes as the shoots emerge and ease the foliage through. This cover can be removed about a month later, enlarging the holes first to allow the plants to "harden off" and acclimatize to the weather.
It is recommended to plant early potatoes under black plastic sheeting to exclude light and remove the need to earth up the potatoes. Cut cross shaped splits into the plastic and plant the seed potatoes through this. This should not be done with maincrop potatoes.
In northern areas the seed potatoes are "sprouted" or "chitted". Place the seed potatoes in a shallow tray, cardboard egg boxes are suitable for small amounts, with eyes/buds uppermost. Keep in a cool, frost free room with even light.
If you require a crop of large, early potatoes then leave three sprouts per plant. Rub off any remaining. The more sprouts per tuber, the higher the crop yield, but smaller potatoes.
Plant when the sprouts are up to 1 inch long. The sprouts must be green, if white then there is not enough light. In this case just remove the sprouts and leave to grow again. It is better to plant when the danger of frost is over and the soil temperature has reached about 45°f (7°C), around mid-March.
Make drills 3-6in deep and place in the tubers with sprouts uppermost covering them with at least 1in of soil. Early croppers should be planted 14in apart in rows 17in apart. Maincrop should be planted 15in apart in rows 30in apart. If possible the rows should run North-South for maximum exposure to the sun.
In cooler areas it is better to cover the plants with some protection, such as cloches, clear plastic sheeting or floating film mulch. Cut holes as the shoots emerge and ease the foliage through. This cover can be removed about a month later, enlarging the holes first to allow the plants to "harden off" and acclimatize to the weather.
It is recommended to plant early potatoes under black plastic sheeting to exclude light and remove the need to earth up the potatoes. Cut cross shaped splits into the plastic and plant the seed potatoes through this. This should not be done with maincrop potatoes.
Watering, feeding and caring for potatoes
Cover at night if there is a threat of frost. If the plants were not grown under black plastic then potatoes need to be earthed up to stop the tubers close to the surface from becoming green and uneatable. When plants are 8-9in tall hoe soil up around the stems to a depth of about 5in.
In dry conditions regularly water early potatoes every 12 days at a rate of 3 gallons/sq yd (16 litres/sq m). Do not water maincrop potatoes until the young potatoes are the size of marbles, then water with at least 5 gallons/sq yd (22 litres/sq m).
Add a liquid feed or nitrogen based top dressing during growth. Do not stop the growth of the foliage as it is supplying food to the tubers but remove flower heads or buds which use up food and nutrients which should be going into the tubers.
In dry conditions regularly water early potatoes every 12 days at a rate of 3 gallons/sq yd (16 litres/sq m). Do not water maincrop potatoes until the young potatoes are the size of marbles, then water with at least 5 gallons/sq yd (22 litres/sq m).
Add a liquid feed or nitrogen based top dressing during growth. Do not stop the growth of the foliage as it is supplying food to the tubers but remove flower heads or buds which use up food and nutrients which should be going into the tubers.
Harvesting potatoes
Harvest potatoes when foliage starts to turn yellow and die. New potatoes can be harvested just before the first flowers open. These produce very few potatoes per plant so lift the whole plant. New potatoes grown under black plastic can be harvested by lifting the sheeting as they are on the surface.
Maincrop potatoes should be left as long as possible. In autumn - early September at the earliest - cut the stems of each plant to 2in above ground level then leave for another two weeks. This hardens the skin before lifting. In warm, wet areas there is a chance of potato blight so cut the foliage in late summer and burn it. Lift the potatoes two weeks later.
Lift the potatoes, remove excess soil and leave in the sun for two hours then store in paper sacks in a cool, dark, frost free place.
Maincrop potatoes should be left as long as possible. In autumn - early September at the earliest - cut the stems of each plant to 2in above ground level then leave for another two weeks. This hardens the skin before lifting. In warm, wet areas there is a chance of potato blight so cut the foliage in late summer and burn it. Lift the potatoes two weeks later.
Lift the potatoes, remove excess soil and leave in the sun for two hours then store in paper sacks in a cool, dark, frost free place.
