Soil Requirements Potatoes need a deep, free-draining and rich soil. Add plenty of well-rotted organic material at the time of digging over the soil, preferably in advance of planting out. Do not plant potatoes on ground that held potatoes or tomatoes the year before.
Seed Always choose certified seed that is free from virus disease. The best seed potatoes are about the size of an egg - try to resist the temptation to take the largest potatoes! About four weeks before planting place seed potatoes in a tray or empty egg carton with the eyes (the growth buds) up and leave in a light, frost-free place to 'chit' or shoot. When the shoots are about 2cm long they are ready for planting out.
Planting Early potatoes are planted in early mid spring. These mature and are ready for digging by early summer; some may be ready for your Christmas dinner depending on your area. The second crop is planted from mid-spring to early summer and is harvested from mid-summer onwards. Main crop potatoes are planted from mid to late spring and harvested from early autumn. Only main crop varieties are suitable for storing.
Dig a trench 10-15 cm deep and place the seed potatoes 30 cm apart (40 cm for second and main crop potatoes). Place them with the eyes (shoots) uppermost. Cover the trench with a low ridge of soil. Rows should be 60cm apart.
Care As the shoots emerge through the soil, 'earth up', that is, rake more soil up on to the ridge, covering all but a few centimetres of the new leaves and keeping them away from the light.
Repeat after about three weeks. In this way you can keep the roots moist and keep the growing potatoes away from light. You can grow the potatoes under black plastic but this is not necessary if you mound the soil regularly. Potatoes turn green and poisonous when exposed to light. Water well in dry periods.
Potatoes 'earthed up'
Harvest Dig early and second crop potatoes as required. Main crop potatoes can be lifted in the autumn, leaving in the ground as long as possible.
Store in a dark, frost-free place, preferably in hessian or paper sacks.
Pest and Diseases Slugs and wireworms are the worst potato pests. Wireworms are present in some newly dug ground and cause needle-sized hole in the potatoes.
Potato blight is the worst disease, and is a fungal infection that is hard to control once established. Plant blight-resistant varieties and use crop rotation to avoid planting potatoes in the same place two years running to prevent the disease taking hold. Do not plant potatoes on ground that held tomatoes the year before.
Potatoes ready to eat
Potatoes for Small Spaces Fresh potatoes have a flavour all of their own. But how do you grow potatoes if you only have a tiny garden, and how to get them started before the frosts have passed? Grow your potatoes in a bag.
Place the potatoes in an egg box with the eyes up, the baby shoots will grow from the eyes. Place them in a cool but light place until they begin to shoot and show little green fat leaves.
Fill a plastic bag one-third full of soil and make a few holes with a screwdriver in the bottom of the bag so that water can drain away and the soil inside the bag does not become waterlogged. (Use a potting compost but not compost from the heap. Potting compost has a mixture of soil and compost)
Plant 2 or 3 potatoes in the bag, with their shoots pointing upwards. Cover with potting compost so that the bag is half-full. Give the bag a good watering and place it outside in a sheltered place where it will not get frost.
When the shoots are 15-30cm tall, you can add more compost until the bag is completely full. This is called earthing-up and it encourages the potatoes to make more stems, and more potatoes, as well as stopping light reaching the potatoes that have already formed.
Harvesting is about 10-12 weeks after planting.
You can also use this method to grow potatoes inside old car tyres, starting with two tyres and then adding tyres, and soil, as the potatoes grow.