How to grow potatoes
Boiled, mashed, baked or cut into chips – potatoes are hugely versatile, and a staple food for most households. Whether you use potatoes to grow your own roast dinner or cool them and added to tasty salads, potatoes are a great investment in space and time that will give every home a tasty reward that can be stored for months.
Glossary of potato terms
Tubers are various types of plant structures that are enlarged to store nutrients. They are utilised by plants to survive the winter or dry months, to provide energy and nutrients for regrowth during the next growing season.
A potato that is intended for replanting to produce a new potato - and thus more tubers.
These are the best choice if you want to grow small, new potatoes. Plant up from the end of February to late May, and the first early potatoes will be ready to harvest approximately 10 weeks from the planting date. Ideal for growing in bags or containers.
Maincrop potato varieties produce larger potatoes perfect for baking and roasting. For best results, 'chit' the tubers and then plant up between March and mid-May. The potatoes will be ready for harvest approximately 20 weeks following from then.
Varieties of potato
The texture of cooked potatoes varies between waxy and flowery and some are best for boiling, others for roasting and even more for chips. For example ‘Red Duke of York’ is useless when boiled, as it falls apart, but for roast potatoes or mashed there is nothing to beat it. For examples of the variety available check out the table below:
|First Earlies||Second Earlies||Maincrop||Salad|
|Foremost||Wilja||Romano||Pink Fir Apple|
Growing potatoes: soil and position
Potatoes will grow in almost any soil, however, they cultivate much better if the soil is enriched with heaps of organic matter. Potatoes grow best in an acid soil so add well-rotted manure and garden compost. It is also important that you do not lime soil at any time.
How to grow potatoes in your garden
How to grow potatoes in grow bags
After chitting your potatoes, take five or so tubers and plant into your bag specifically designed for growing potatoes, around 10-12 centimetres deep, with the shoots facing upwards. Add more compost into the bag until each tuber is covered with a gap of around 5 centimetres to the top of the bag.
An application of a high potash fertiliser at the rate suggested on the pack will increase yields. Avoid fertilisers high in nitrogen as these will delay maturity of the crop.
Water the compost as to make sure to keep it moist, especially around flowering time. Do not saturate the compost as this will cause severe rot!
First early potatoes arrive around June/July time, when the leaves have fully matured and opened. Second earlies and salad can be harvested and eaten at the same time of year.
For main-crop potatoes, look to store your potatoes in a hessian bag in a cool, dry environment. The potatoes will be ready to harvest once there is a yellow colouring on the stems and leaves. Then remove the stems and harvest 7 days later in full.
For plenty of small ‘new’ potatoes ready to eat in July, plant a variety known as ‘early’. For a large crop of big tubers that will be ready in September and can be stored for months, go for a ‘maincrop’.
Growing seed potatoes
By buying seed potatoes, you are able to begin growing them before planting them in January/February time. Seed potatoes are actually small tubers specifically grown for the purpose. Remember, always buy certified seed potatoes - this way you will then know they are free from virus infections.
Seed potatoes are normally available in the first few months of the year, well before they can be planted outside.
To get them growing when you buy them, place them in egg boxes or a seed tray, with the end with most eyes or buds facing upwards. Stand them somewhere that is cool, but frost-free, and in good light. The aim is to produce small, sturdy, green shoots. To get the biggest crops it’s important to ‘chit’ your seed before planting. This technique called ‘chitting’, is said to improve yields, but probably is used only to gain a few weeks in the time needed for growing earlies in the ground and to provide the right conditions for storage.
There are a number of methods for growing potatoes – for example, under black polythene or in large containers. To plant using black polythene, plant the tubers through the black polythene. An advantage of this method is that there is no longer a need to earth up the new potatoes so there is no digging involved to harvest them. If you choose to use containers, line the bottom of the container (15cm/6in) with potting compost and then plant the tuber below.
Keep adding the compost until the container is full, as the stems begin to grow. Remember, newly emerging foliage is susceptible to damaging frost – avoid this by earthing up with the surrounding soil or by covering the shoots with a fleece.
Planting seed potatoes
The tubers are ready to plant when the shoots are about 2.5cm (1 in) long. In late March or April dig a trench 15cm (6in) deep and plant the potatoes. Carefully push your seed potato (with the shoots facing upwards) into the loosened compost leaving a gap of 30cm (12in) between each one. Take care not to damage the shoots as you plant the seeds and ensure the potatoes are evenly spaced and not touching each other. Leave a space of 60cm (2ft) between rows. Fill the trench with soil mixed with garden compost, or other organic matter, for harvesting from the end of June.
Caring for potatoes
When the green shoots have grown to 20-30cm (8in-1ft) tall pull some extra soil around the stems to make a ridge. This soil is to exclude light from the potatoes that are forming on the surface. Water in dry weather. A liquid feed every fortnight of a general fertiliser can help grow yield.
Common potato problems
This is a common disease that occurs in damp, warm summers. Initially, a brown watery rot will rapidly spread affecting both the stem and the leaves. In terms of tubers, they turn a reddish-brown colour when infected. They appear firm to begin with, but then develop into a soft rot below the skin. Potato blight is a difficult one to remedy, as unfortunately once it has struck, it is not easy to stop. There is currently no chemical product that can be used to fight blight, however you can apply a protectant in June if you predict the summer to be a wet one.
A common disease, blackleg is a bacterial disease which causes blackened rotting at the base of the stem. Infection can cause stunted growth and yellow-coloured stems. Tubers may turn grey/brown and rotten if they continue to form. To remedy this problem, destroy all infected potatoes and rotate crops. It is advisable to purchase resilient potatoes varieties to avoid this problem – varieties such as ‘Charlotte’ and ‘Pixie’ are best.
Causing scab-like lesions on the surface of the potato, this disease is easily removed from the outer skin by peeling and does not affect the taste of the potato itself. There is no remedy for potato scab as such as you most likely will not recognise the issue until harvest time. The best advice is to keep your potatoes well watered as scab worsens in dry weather.
Potato rot is a significant problem that follows a wet growing season, especially if the tubers are lifted from wet soil. The best way to remedy potato rot, is to use good quality sees tubers that are resistant certified, and ensure you harvest at a time when the soil is not wet nor dry. Also, make sure to store your potatoes in cool and dry conditions.
A huge nuisance where potatoes are concerned, slugs will eat holes in the potato leaves, and will burrow into the tubers themselves. The tell-tale sign of a slug problem is the slime trail visible on the soil near your crop, and also on the leaves themselves. There are so many ways to remedy this common problem, the best advice is to experiment and see which solution best suits your problem.
Earlies will be ready for digging when the flowers have all fully opened in June/July. The tubers are ready to harvest when they are the size of hen’s eggs. Second earlier in July and August; maincrop or lates from late August to September. Maincrops are suitable for storage until the foliage turns yellow and then cut and remove. Leave the tubers for ten days before harvesting and make sure to leave them for a few hours to dry before you store them. Reject any potatoes that are green - they are poisonous!