Potato

Why Grow Potatoes?

The potato is the most common home grown vegetable, with its wide ranging culinary uses it is clear to see why. Potatoes originate from the South Americas, with the first arriving on our shores in the 16th century, they have now become a part of the UK’s staple diet.

Potatoes are relatively easy to grow, but with so many varieties and uses it can be difficult to decide which ones to grow. With this in mind we have created this guide to growing potatoes, how to get the best results, some ideas for their uses in the kitchen and some information on individual varieties to help you decide which ones to grow.

Quick Facts
Botanical Name : Solanum tuberosum
Planting Time : First Earlies – Late March
Second Earlies – Early to Mid April
Maincrop – Mid to Late April
Harvest Time : First Earlies – June to July
Second Earlies – July to August
Maincrop
– August if for immediate use
– September to October if for storage
Hardiness : Not hardy – Protect From Frost
Position : Full Sun, Sheltered from strong winds
Soil Type : Any, fertilized soil improves yields, but avoid soil with a high lime content.
If you cannot avoid soil high lime content, choose a variety with a good resistance to Common Scab.
Average Plant Height : 60-75cm / 24-30in
Spacing : Earlies – 30cm / 12in
Maincrop – 38-45cm / 15-18in
Spread : 60-75cm / 24-30in
Glossary

There are a few terms that are used when we talk about potatoes, for those who are new to growing potatoes we have made a quick list of terms and their meanings to help you on your way.

Term
Explanation
Chitting Chitting is the term given to the process of stimulating the seed potatoes to start growing and produce small shoots. See below for more information on chitting seed potatoes.
Haulm This term refers to the stalk and leaves of the potato plant.
Greening This happens when the growing potato tubers are exposed to light and turn green. This is why we “Earth up” potato plants.
Earthing Up This is the process of adding more soil around the base of the potato plants to make sure developing tubers are kept out of sunlight and prevent “greening”, it is what gives potato rows their characteristic ridges.
Bulking Up This is when the newly formed tubers begin to increase in size and start growing into something worth harvesting.
Eyes These are the small round dimples on the skin of a potato, they are where the tuber shoots will emerge from.
Rose end This is the end of the potato with the most eyes.
Second Growth This happens when potato plants stop the growth of their tubers during periods of drought, then resume growth when the drought ends. This can cause hollow, cracked or odd shaped tubers to form, it can be avoided by keeping the plants watered during dry spells.
Soil and Preparation

Potatoes will grow in almost any soil and in fact are often used to ‘Clean’ a plot before using it for other vegetables. The dense canopy helps to kill off weeds and the digging and earthing up of the plants helps to break up the soil.

To get the best yields from your crop, deep, fertile soil which retains moisture is best. Dig your potato plot in the autumn, you can improve the moisture retention of the soil by digging in some well rotted manure at the same time. Avoid liming the soil as this can encourage scab.

Towards the end of February you can start making preparations to plant your potatoes. Dig over your plot again, breaking up any lumps that have formed. Your plot is now ready for planting.

Seeds, Chitting and Planting

Seeds
Potatoes are usually grown from small tubers known as seed potatoes, they are not strictly seeds but are a lot more reliable for gardeners and farmers. A lot of modern varieties do not actually produce “True seed” and can only be grown from tubers, growing potatoes from true seed is usually only done by breeders to produce new varieties.

Seed potatoes are usually about the size of a hen’s egg, although this is not always the case. The shape and colour can vary depending on variety, most are round to oval-round and white/yellow or red in colour but some such as Pink Fir Apple are shaped like fingers!

One thing they all have in common is that they should be firm and free from disease, you should discard any that are soft and generally buying fresh certified seed each year can help keep disease at bay. All seed bought from reputable companies should be fully certified and free from disease, ours certainly are.

Chitting
First and Second Earlies do really need chitting, if planted without chitting they will still grow but they will not crop so early and as that is usually the reason for planting them it defeats the object of the exercise!

Maincrops can be chitted although not essential it does get them off to a quicker start and can produce better and/or faster yielding plants but as they are generally left growing for longer it is not as important as with the earlies.

You can start chitting your potatoes from January but avoid planting out until the risk of heavy frosts has past – usually around March in the south and April in more northern areas.

To Chit you potatoes, place them in a single layer on a tray – an egg tray is perfect for this – with the rose end facing upwards. Store the tray somewhere cool and light, but make sure it is frost free and not in direct sunlight.

In a few weeks they should begin sprouting, after approximately six weeks the shoots should be about 5cm (2in) long, strong and ready for planting out, if the weather is not favourable then keep your seed potatoes chitting for a bit longer, less harm will come of them this way than from planting them out too early.

Planting
You can plant out your seed potatoes when the risk of heavy frost has past, this is usually around the middle of March in the south and a few weeks later further north.

Before planting out your potatoes you will need to do a quick bit of preparation on your plot. Mark out your row spacings – 60cm (24in) for Earlies or 75cm (30in) for Maincrops – using a hoe or spade draw back the soil from the centre of the row to create a trench about 10-15cm (4-6in) deep, apply a general fertilizer at a rate of about 50g per square metre (1 ½oz per square yard) to the bottom of the trench and cover with a thin layer of soil.

Now you are ready to plant your seed potatoes, carefully remove them from their tray and place them in the trench, with the shoots pointing upwards, at spacing of about 30cm (12in) for earlies and 38-45cm (15-18in) for maincrops. Use a few handfuls of soil to keep them upright if they decide they want to ‘lay down’. Once they are all in place carefully pull the soil back over them using a hoe, leaving a slight ridge in the centre of the row. Now apply more fertilizer – at the same rate as above – over the top of the soil you have just replaced.

For earlies, if the haulms are showing and there is a risk of frost, draw up more soil from between the rows and re-cover them. This should help protect them from the worst of it.

Caring for your Crop

When the haulms of your potatoes reach about 20cm (8in) high it is time to earth them up. Carefully dig through the soil between your rows and remove any weeds, making sure you do not damage your potatoes. Using a hoe, draw the soil in towards the haulms. The aim is to produce a flat-topped ridge about 15cm (6in) high.

Make sure your potatoes are kept moist throughout their growing season, giving them a good soak every 10 days during dry spells. If you allow them to dry out during the growing season there is a possibility of encouraging Common Scab, damage being caused to your crop from second growth, as well as a considerably reduced yield.

Harvesting

Earlies should be ready for harvest about 9-12 weeks from planting, normally about the time the flowers are fully open. To check, carefully remove soil from a small section of the ridge and see what size the potatoes are. Usually new potatoes are harvested when they are about the size of a hens egg, if you are happy with the size of your potatoes then you can begin harvesting. If not leave them for a while longer.

Maincrops usually take around 14 weeks to be ready, if you are wanting to store you potatoes, wait for the haulms to turn brown and then cut them down to soil level. Leave the tubers in the ground for a further 10 days before harvesting.

It is best, if possible to harvest your potatoes on a dry day. Using a flat-tined fork, insert it into the ridge away from the haulms and gently lift along the trench towards the haulms. If you are going to store the potatoes lay them on the surface and leave them to dry for a few hours.

Storage

You can store potatoes for several months if done correctly. Make sure they are fully dry and undamaged, package them in paper or hessian sacks and keep them in a cool, dark and dry place. Do not store in plastic bags as they can sweat which will cause them to rot. Check them every now and then to make sure they are all still in good condition and remove any that look rotten or damaged.

New potatoes can be kept in a polythene bag in the fridge, and will stay fresh for about 2 weeks.