Home grown potatoes are one of the most satisfying crops to grow in the garden. It’s quite easy to produce a good crop and tubers dug from the garden taste so much better than those from the shops. In fact the only way to enjoy the truly delicious flavour of the first new potatoes of summer, is to dig your own and hurry them to the kitchen as the sweet taste can diminish even a few hours from lifting. Again, as autumn approaches, it is so much better to select your very best tubers for winter storage whilst using tubers of lesser quality first.
Potatoes will tolerate a wide variety of soil types and weather conditions and therefore good crops can be expected throughout the UK. In the garden it is quite possible, by varying growing techniques, to produce the first earlies under protection in April and still be eating ‘new’ potatoes the following Christmas.
Far from being a stodgy accompaniment to the meal, potatoes are a valuable food with whole tubers containing important levels of vitamins as well as valuable carbohydrates and very useful levels of proteins.
Care of Seed Potatoes
To get the best crops and have a good chance of avoiding pest and disease problems it is vital to plant healthy high quality seed. All our seed is raised by specialist growers and is inspected and certified; you will see the seed grade and certificate number on the bag label.
Ideally your seed potatoes should arrive some weeks before you wish to plant them. This will give plenty of time for ‘chitting’ – the development of strong healthy green shoots. To this end the potatoes should be unpacked completely and laid in a single layer in shallow trays or similar – if you have them fibre egg trays are perfect too! Tubers should be placed such that the rose end (where you will see the most buds or ‘eyes’) should face uppermost.
Place your seed potatoes in a cool, well lit place where there is no risk of frost, a temperature of 7˚C (45˚F) is ideal. Under such conditions short, stocky dark green ‘chits’ will form in a few weeks and remain in good condition for some time until it can be planted. The first and largest chits to form are known as primaries and are the most important. Removing some of the smaller secondary chits before planting will usually lead to the resulting crop having fewer but larger tubers – worth knowing if you are after some hefty bakers!
Planting well chitted seed is of the greatest advantage with early varieties when it can speed up growth by as much as three weeks. With maincrops, chitting is less critical but still advisable as crops will mature before poor weather sets in and slug damage increases.
Site and Preparation
Potatoes are quite forgiving of soil types and will give an acceptable crop under a wide range of conditions. They do best though in rich, well cultivated soils with good drainage and fertility. Avoid if possible any ground that has grown potatoes within 3 or 4 years.
Care and preparation both before and after planting will almost always bring dividends both in yield and quality. Ideally pH should be just on the acid side of neutral. If your soil regularly needs liming to correct acidity this should not be done if potatoes are to be planted as liming can lead to scab disease. In these circumstances lime after the potatoes have been lifted.
If at all possible the site should be well dug in autumn and a generous amount of manure or garden compost incorporated. In this way winter frosts will help to break down the soil and the manure will release helpful nutrients and aid structure. Cultivate the soil well as soon as conditions in spring allow, breaking down large clods to give a good tilth and incorporating a potash rich fertiliser such as our own Potato Fertiliser.
Earlies can be planted anytime from around mid March and even sooner in the mildest regions. Maincrops can then be planted from early April. Do not be tempted to plant too soon if conditions are not favourable – seed planted into moist warming soil (minimum 7˚C, 45˚F) will do well and invariably overtake that planted sooner into cold wet conditions.
To plant, draw out shallow trenches 10-15cm (4-6in) deep in rows 60cm (24in) apart and plant seed tubers at a spacing of 38cm (15in). If earlies are being planted these distances can be reduced such that rows are 50cm (20in) apart and tubers are spaced at 30cm (12in) as earlies need less space due to their shorter growing season. Draw the soil over the seed potatoes using a rake or hoe to cover and form ridges over the rows. Provided soil is moist watering should not be necessary at this stage.
The first shoots should emerge from the ridges after 3-4 weeks – sooner with well chitted seed in warm soil. The rows should be further ‘ridged’ up to cover shoots and this can be repeated if maincrops are grown. Any developing tubers that lie shallowly will thus be prevented from greening. A deep ridge formed for tubers to develop in will also have a controlling effect on weeds. Ridging up will also offer some protection against any late frosts but should these be forecast additional measures such as covering with fleece will prevent foliage damage which could otherwise delay the crop.
The developing crop needs moisture, which is usually in good supply in the British spring! In periods of very dry weather water if possible, this is particularly important at the time when tubers are first forming – for earlies about 5-6 weeks after planting and a week or so later for maincrops. Watering in the early morning or late evening will be most effective.
First earlies should be ready to dig between 8 and 12 weeks from planting, depending on season and variety. It is often said that earlies are ready to be dug once flowers start to appear. In reality, because flowering time and frequency can be very variable between varieties, it is best to just dig a root and see!
The immature tubers we know as new potatoes owe their unique taste partly to lower levels of starch and higher levels of plant sugars in the tubers. A while after lifting this balance changes as starch increases and some of the sweetness is lost. The skins also toughen after a while and become less easy to remove (if that is your preference). We therefore recommend that you only dig as many new potatoes as you wish to cook, in this way you will experience them at their most delicious although, of course, it is fine to save some cooked ones for use in salads.
Second early varieties can either be used as new potatoes or stored for later use. This is largely a matter of preference depending on how quickly you consume them!
Whilst maincrop potatoes can be easily dug for immediate use many of them are stored, once mature for use through the autumn and winter. It is therefore particularly important to lift them in good condition. Firstly it is important that the crop has matured and the skins are well set. Usually by early autumn the foliage (haulm) will have died back naturally indicating that the crop is ready for lifting. If haulms are still green in October they are best removed as this will cause any immature tubers to set their skins. Lifting should take place before late October as risk of slug attack increases in autumn.
Dig and remove all the tubers from the soil ensuring that none remain as any small ‘groundkeepers’ will be a nuisance weed next spring as well as potentially carrying disease forward. If possible allow dug tubers to dry either by leaving on the surface for a few hours or laying out for a day or so in trays indoors.
Discard any damaged or diseased tubers and then store for the winter in paper or, ideally, hessian sacks. The sacks should be of sufficient thickness to exclude light as this will cause stored tubers to turn green. Do not keep in polythene sacks as these will quickly lead to rots setting in.
Store the potatoes in a cool, airy, frost free place and inspect regularly for the few that may deteriorate. In this way well grown and safely lifted and stored potatoes will keep right through to the spring.