Potatoes are an easy crop for the home gardener
It sometimes seems that only Tasmanians really appreciate their potatoes. They grow Up-to-Dates, a variety dating from the 1830s or earlier, for baking. The Southern Tasmanian Pink Eye is the only potato that can be frozen fresh. It is a waxy, yellow fleshed variety that only does well where it was bred. Its flavour is incomparable, despite its meagre yield.
Potatoes and milk, it is said, provide an almost complete diet. Indeed, the Irish were allowed precious little else for many years under British rule. The Irish have become synonymous with potatoes, not just because they died in their millions during the potato famines, but because of a unique method of growing them. It is called lazy bed gardening.
The seed tubers were laid on the turf within an area some 1.2-1.5 metres across and as long as required. The surrounding turf was excavated and placed in layers on top, interspersed with cow manure. The turfs were laid grass side down. Since the climate in Ireland provides copious rainfall, that was all there was to it, until harvest. It is very similar to the approach used by the modern day organic gardener, except the turf is replaced by straw or hay. If hay is used, it should be shaken on loosely, to allow the weed seeds to fall to the ground, before being compacted, by walking on it. The weeds growing where the potatoes are to be grown should be trampled rather than cut, as cutting stimulates them. Truly remarkable yields are possible using this approach. The spacing between tubers is generally about 30 cm each way. 'Bandicooting', or premature stealing of potatoes from the growing plant, is easier when the tubers are growing under mulch. Just lift the mulch, take what you fancy and replace the mulch. Keep your eyes open though. If bandicoots prowl your garden, you might just seize a wriggling, furry creature rather than a cool firm spud. Take it from one who knows. It does make your heart leap. I don't think the bandicoot was too impressed either.
Potatoes are more often grown in rows 750 mm apart. Early potatoes are sown shallowly and 30 cm apart, late varieties 100 mm deep and somewhat further apart. As the potatoes grow, the soil from between the rows is drawn up into a ridge. This protects the tubers from exposure to light, which makes them green and poisonous. It also affords some protection from the potato moth. The ridging process also destroys the weeds that arise, so potatoes are known as a cleaning crop, leaving relatively weed free soil for subsequent crops.
Potatoes are very hungry, the more compost the better, though they are more tolerant of straight animal manure than any other crop. They crave copious quantities of potash, which can be supplied with well-wilted comfrey in the trenches. If wilting does not kill the comfrey, you will create a new permanent patch of comfrey; it is almost impossible to eradicate without herbicides. Young bracken fronds are also a good source of potash.
Potatoes cannot abide lime. It makes their skins scabby. Wood ashes, otherwise a good source of potash should not be used. They do need copious quantities of water, preferably from flood irrigation. The major disease of potatoes is blight, and this is encouraged by humid conditions. If blight has appeared in your district, wet the leaves of the plants thoroughly with Bordeaux mixture (copper sulphate and lime). Do not use this as a preventive, the copper is toxic to earthworms and the fungicidal property of the spray is just as effective against beneficial soil fungi as it is against the dreaded blight. Should blight catch you out, remove the dead tops and leave the ridges alone and undisturbed for some time. The tubers are only affected if the spores from the leaves come into contact with them.
Early potatoes are lifted before maturity, while the skins are tender and easily rubbed off. Late potatoes are allowed to die off before the tubers are lifted and allowed to dry and harden for a few hours before storage. Do not expose them to the light for too long, or they will green. Do not attempt to store tubers damaged by digging. They will rot. Store them in a dark, cool shed, away from light and all danger of frost. Rats love spuds so make sure you take precautions to prevent them gaining access.
You will read that you should only grow your potatoes from certified seed. This advice is good as far as it goes. Under average conditions, aphis transmit virus disease to potatoes that are transmitted via the tubers. As the viral organisms build up, they reduce each subsequent crop by about 20%. Of course, organic gardeners are not average and will have been giving their crop a fortnightly spray of liquid seaweed, an aphis repellent and all-round tonic. The ground will have been manured with good, rich compost, so the plants will resist invasion by the viruses. You can save quite a bit of money by growing your own seed from a planting of certified. The time taken for subsequent home-saved seed to run out could be five years or more. I know of one organic grower whose seed is just as good after more than twenty years, as the mother seed used to grow certified.
Using home saved seed is the only way you are going to get some of the older, almost extinct varieties. The turning of food into a commodity has led to the creation of general purpose vegetables that are not particularly good for any one thing. The Up-to-Dates mentioned are the best for baking, but they turn to water when boiled. The Pink Eye makes lousy chips, but is unsurpassed boiled or steamed. The King Edward in the right soil can rival the Pink Eye for flavour, but requires double digging to give of its best. A row of Pink Eyes in my garden was blasted by the blight while an adjacent row of Tasmans remained untouched. You must experiment to discover the best for your district and palate. The rewards are greater than you probably realise.
Potatoes have an undeserved reputation as being bland and fattening. I am not normally inclined to hatred, but the originator of these filthy rumours should be shot if he/she is still alive. Potatoes are mostly water and the balance is mostly minerals and high quality protein. There are less calories in French fry chips than the same weight of unbuttered bread, and most of the calories come from the cooking oil. To maintain body weight requires about 3.5 kg of potatoes per day for the average person, a mammoth feat of eating for anyone.
Sow your early potatoes shortly before the last expected frost. Early potatoes should be chitted, that is left in a light airy place to sprout. The sprouts must not get too long and lanky, or they are too easily knocked off. Large seed tubers can be cut to one eye on each piece. Some growers dust the cut surfaces with cement, but this is not necessary if they are planted immediately after cutting. Each piece should be about 50 gms. Main crop spuds are sown later, after all danger of frost is past and the soil has warmed. Frost on the tops will kill them. There is no need to chit maincrop potatoes.