Do You Know Your Potatoes?

Auckland Star, Volume LXIX, Issue 226, 24 September 1938, Page 18 (Supplement)

Do You Know Your Potatoes?

Garden Notes

Raising new varieties of potatoes from seed is expensive and costly. Seedlings have to be grown for several years to prove that they are distinct improvements upon existing varieties. They must also be tried out for cropping, disease-resisting and other qualities.

The i«l oa 1 potato must be a good grower, with upstanding stem and thick leathery leaves. Tuliers should lie round or oval, eves or ltuds level with the surface, with a rough "crackly"' skin, of a uniform size, of a high quality when ripe and possessing long-keeping qualities.

Quality depend* on the starch contained in the tuber. A good-quality tuber should contain 1"> to 20 per cent. Starch is produced by material absorbed by the roots, transmitted to the leave* which take in-carbonic acid gas from the air and split up the constituent elements. These again combine and are converted into sugar, which is carried down the stems to the ends of strong, underground branches, where it changes back into starch and is stored up, forming large swellings— potatoes. I he potatoes are formed on thickened root-like steins just above the actual roots and not on the roots themselves.

Large, stout leaves directly exposed to the sun prepare live to 1() times more starch than thin, shaded leaves will. Crowded and partial shaded leaves can only produce limited quantities of starch, hence the crop is diminished or limited accordingly.

Staking is not usually practised and with a general crop it would l>e impossible, but when growing for exhibition it will be found a great asset. The young tubers are produced on stems sent out just above the old set or tuber, hence the need for "moulding"' or "earthing" the plant. Oround should be well prepared by digging or trenching. It should also be allowed to weather between the time of digging and planting. Soil best suite.l is of a loamy, calcareous, sandy nature, but in actual practice almost any soil can be made to produce a fair crop of tubers. Old soils rich in humus, and those inclined to be peaty will produce sappy foliage which is quickly attacked by disease.

The following can be taken as a complete potato manure: — Superphosphate, loz j,er square yard; 2jcwt per acre. Bonedust, loz per square yard; — A<-\\ t per acre. Sulphate ammonia and nitrate of soda, Joz per square yard: 2Acwt per acre. Sulphate ammonia or nitrate should he applied in two lots—one. that i*. half, when the tops arc six inches high: the other, three weeks later. Potash at '.oz to yard or 1 Acwt to acre can be added on some soils, but u-e of pota-li is being discredited in the light of recent experiments which have proved that laige supplies of nitrogen are more im-

portant than potash.' Xitkophoska at j the rate of 2c wt per acre. Agri: Salt at i 2ozs to square yard sets free potash and acts as a mild sterilising agent. Kish manure is excellent and. used at the rate of 4oz per square yard, or 2oz,

f'tsh and 2oz su;>er. gives good result s . Wood a-hc- are good and can he applied at almost any time. It i- funi- .>r live years after sowing before merit- or demerit* can be ascertained. In dealing wiili new or expensive ports, plants can be raised by cut - • tings. Tubers are laid on a shelf; as ; the young shoots develop they are cut i off. made into cuttings, placed ill a suitable medium and. after rooting, are | putted up. grown on till large enough. ; then hardened oil' and eventually planted joui. I lie j.i and conditions neces-jt-ary are similar to that required by \ t lie da hlia.

Tubers tn he used for seed should he sprouted l.i-fore planting. Stand thi'in in !>o\es. i.i-i' end upwards, and allow them full 1 iht. This en.-ures dark. green. \ igorou* -piMiiti- not easily hroken when handled for planting-.

Onlv cood-shaped, medium-sized, clean tutors should be used for seed purposes. Tubers of 2oz weight are best. Any showing weak, thread-like ehoots mu6t be thrown out, as they are useless. Cutting of tubers is recommended if the tubers are large. Unripe seed or sets from a crop lifted after the plants (lower and before the tubers properly nature gives best result*. Reducing shoots to two or three is an advantage it the tubers are to be used for exhibit ion.

The distance apart of planting varies according to the variety, but in every ease allow sufficient spare for the plant* to develop to their full extent. Some earlv sorts with short tops can be planted a- close as 18 inches, but with the majority :ii» to .!(» inches is necc*Mirv. In the drills the sets should be placed nine to 12 inches apart.

When planting, draw drills and scatter manure on the sides so that it i* mixed with the soil when the drills are closed. When the crop shows through the ground, the hoe and fork should be u>-e<rfreely until the tops are too large to allow of it. .Moulding up should start when the to|*« are six inches high and continued at intervals until they are too large. The crop is ready for lifting when the foliage begins to assume a yellowish colour. After 'ifting. collect the haulm and burn it. Do not leave it lying about to spread disease.

Spraying i- nmv part of potato-grow-ing. for. although the disease has h»-t some of its previous virulence, it can truthfully lie said that no crop is entirely free. For spraying ti*e liordeaux. 4 4-4(1. or sodaTiordeaux. 4-.">-4(». or diwt with a line grade of sulphur. Jhe liivt spray should he applied when the tops are ju-t through the soil, again when six inches high. and a;jam when a foot high. In wet seasons or in contaminated (.Mound it may be necessary to give more applications.

Clean ground and clean stock are a irreat factor in production of a good crop. If one is selecting one's own seed, it should be picked out at the time of digging, chosen only from roots showing good cropping and disease-resisting qualities. This is best done before tlie crop reaches maturity. The best and most vigorous roots can then be picked out. The s£ts so selected should be boxed, sprouted and replanted as soon as possible to produce a late crop of "unripe" ■seed.

Tubers should 1)0 stored in a dark, cool, well-ventilated shed and covered with soil or sand. To store them in bags or to leave them uncovered is to invite attacks by tlie potato moth.