In the UK we eat somewhere in the region of 4 million tons of potatoes each year, of which nearly 3 million tons are bought by the housewife in shops and supermarkets, which gives some idea of the place this vegetable occupies in our eating habits. The potato is a most versatile vegetable having a high carbohydrate rating and the highest protein of the root vegetables besides being high in vitamins, particularly C. It is difficult to imagine an acceptable substitute for it. Closely related to the tomato and aubergine it is prone to the same diseases. Though grown widely by farmers the home produced potato has the advantage of freshness, better taste and choice of variety.
There is a particular variety of potato for a particular type of soil, but this does not mean that those varieties will not perform well in other soils, it means that you should find out from other growers in your area or on site the varieties which in their experience do consistently well in local conditions. To say that potatoes will give you an average return in any sort of land is not the answer in fact most varieties will need well manured land, and high loam soils with a fairly high phosphate/potash level will score over others. Potatoes follow greens in the correct rotation system and if the land has been well prepared the year previous for say cauliflowers or sprouts then you are off to a good start if you leave it rough for the winter and give dressing in general fertiliser a fortnight or so before planting, such as BTD or a potato fertiliser with an NPK of 20.20.20 On newly dug ground such as grassland, rake in insecticide if there is any evidence of wireworm or eelworm.
The potatoes from which your crops are grown are dormant tubers which would be better referred to as “sets” since they are not seeds (the seeds are to be found in marble size green fruits at the top of the haulms after flowering, which if sown, would not provide suitable size potatoes for several years). Certified sets are produced in areas of clean disease free environs in for instance the Grampian Hills of Scotland would be certified by DEFRA. You would thus know that your sets carry no disease. Leading horticultural stockists sell Irish, Welsh or Scottish certified “seed” potatoes and you should resist the temptation to use the ones from the bottom of your shopping bag since you do not know their history nor how they will perform nor if you will be infecting your own land with disease. The ideal size for seed potatoes is 75 – 100g. Large sets should not be cut, as this encourages rotting. On good land using a main crop variety planting 2 – 3 sets per sq. foot (21-32 sq. metre) at 76cm spacing between rows should give a reasonable return. Aim for 8 “eyes” per sq. foot (86 per sq. metre). If you are a family of 2 adults and 2 children and consider yourselves average for potato consumption, then as a rough guide you will need to plant 28lbs of earlies and 42 lbs of main crop if you are to provide a supply through “winter” but since this would need a planting area of about 150 Sq. yards or about half the standard allotment, you may have to settle for a smaller planting in order to accommodate your other crops, so it is usually the case early varieties are grown when potatoes are at their dearest to buy and the main crops are bought when prices are cheaper, unless you are in sufficient land to grow both.
Having obtained your sets (late January is best) stand them in boxes in full daylight in a frost proof, well ventilated place (a greenhouse is not usually suitable) and with each set having its concentration of “eyes” uppermost the crown end. Over the next 8 weeks or so shoots will emerge from the “eyes” so that at planting time there will be dark green/purple stems about 2! (5.2cm) long, pencil thickness, showing some small leaves which will ensure that your crops are earlier and heavier than they would have been had you obtained them at planting time and planted without chitting.
For best results, first early varieties should be planted in late March – a week or two earlier in southerly areas and sometimes a couple of weeks later in the far north. Harvest mid June onwards. Plant second early varieties mid April and harvest August. Plant main crop at the same time, harvest September onwards. Take out a V shaped furrow with a draw hoe and deep enough to ensure that the sets are covered with about 4/5 inches (10/12cm) of soil. Put slug pellets in the drill before you cover the potatoes. Space the tubers at 12” (30cm) apart for earlies and about 15” (38cm) apart (nothing terrible will happen if these distances are varied an inch or two). Rake the soil level and make sure that it is easily workable between the rows.
Care and Cultivation
When the shoots emerge above ground hoeing may be done to keep down the weeds. It is wise to anticipate frost damage – cover the young leaves with soil, straw or bracken. Wait until the haulms (stems) are about 6-9” (15-23cm) above ground before “earthing up”. This is done to avoid the potatoes becoming “greened” by daylight, a condition which renders them poisonous. This process may be repeated once or twice more during the season until the rows are well mounded – apply slug pellets at each earthing, water well in dry weather. If the haulms produce an abundance of flowers, nip them off. When growth has slowed and the haulms turn yellow the tubers are at maturity, of course you can dig them up as required during the season but leave them to grow for maximum weight. Lifting for storage is best done on a fine day when the potatoes may be left for an hour or two on the ground before being cleaned of soil and put into paper sacks or hessian bags which give some ventilation. Don’t use plastic bags nor put them into any container before being properly dry. Store in the dark, in a well ventilated frost proof store and examine regularly. You can also grow potatoes in pots, buckets and plastic bags. Early varieties are best suited to this type of cultivation. Varieties to grow for best results are subject to conditions as previously stated but here are a few:- First Earlies: Rocket, Maris Bard, Concorde, foremost, Swift, Lady Christi, Winston. Main Crop: Romano, Kirsty, Cara, Pentland Dell, Maris Piper, Desiree. Salad Potatoes: Pink Fir Apple, Ratte, Charlotte, Nicola.
Pests and Diseases
There is no shortage of potato troubles but in the main they are not disastrous. Scab is a “cosmetic” sort of ailment and affects the skins only. There is no remedial treatment and it can be peeled off. Does not affect the tuber internally except in bad cases. Avoid liming. Blackleg is more serious. It is a fungal complaint which attacks the stem at soil level, leaves turn yellow, haulms wither, tubers near the stem rot. Destroy affected plants. Potato root eelworm is by far the most serious common pest. If you see large numbers of haulms go yellow or stunted or distressed quite early in the season, suspect this pest. If only occasional plants are affected it may be due to virus or wireworm. There is no remedy for root cyst nematode (eelworm). You may have to starve it out of the land over a period of many years or use a resistant variety such as Pentland, Javelin or Maris Piper.
Method for Growing Exhibition Quality Potatoes
Fine Spagnum Moss Peat 300 litre bales – put through a shredder, previously used a ¼ inch sieve by hand but have found the shredder works just as well – quicker! Mix (sufficient for 3 potatoes):- 4 x 3 gallon buckets of peat 16oz Calcified Seaweed 16oz BTD This is mixed together in an electric cement mixer, a gallon of water is added during mixing. Once mixed the “mixture” is left in peat bags in the garage for a month or so. 1st week in April – mixture put into bags, we use “polypots” . One potato is put into each bag about 1/3 of the way up.
Bags are then stood on the lawn and well watered. A shallow trench is dug in the garden approximately 3” deep x 12” wide, potato fertilizer is sprinkled in the bottom of the trench and lightly forked in. Then slug pellets are sprinkled in the trench. Bags containing potatoes are then sat in trench approximately 2” apart - loose soil then banked up around bags about half way up. Next trench is taken out about 13” away from the previous row and so it continues for all potatoes. All potatoes are well watered again once in situ