THE VEGETABLE GARDES.

New Zealand Herald, Volume LXIII, Issue 19474, 2 November 1926, Page 14

THE VEGETABLE GARDES.

GROWING KUMARAS. BY S.T.I?. The kumara or sweet potato is a vegetable that was grown extensively l>y the Maoris. In fact, they depended to a large extent on the kumara crop for a good portion of their food, and it was n great favourite with them. With the gardener to-day it is no less a favourite. It is grown wherever there is sufficient space to make it worth while, and where there are reasonable chances of success. This plant is not propagated by meaus of seed, as most crops are. The method of propagation is somewhat similar to that of the ordinary potato. 'the new plants of both grow from the eyes of matured tubers, but the difference between the methods of propagation lies in the manner in which they are grown from the eyes. In the ordinary potato the tubeis are planted where the plants are to be grown, and a number of shoots arising from the one tuber are allowed to grow in a group as one plant. In the case of the sweet potato, however, the tubers are planted in a bed and the shoots which develop are broken off and planted out as single plants. Soil and Preparation. The kumara gives fair returns on most soils, but the best are obtained from a sandy loam with a firm bottom. Th« firm bottom is essential, for, if given a deep soil, the roots will grow down htrongly and form a dense mass, but very few, if any. tubers will develop. The bottom should not bo so firm, however, that it is impervious to water, with the result that the kumara bed becomes waterlogged after a heavy rain There is not much need for fear in this direction if tV season is dry, but, nevertheless, such a soil is undesirable at anv time. Another point in connection villi the soil for the kumara crop is the temperature of the ground. Cultivation tor Kumaras. The kumara is a semi-tropical plant and, therefore, requires a soil in a warm situation. In fact it is essentially a ■warm weather crop and_ can be grovrn only in the summer months. In making preparation for the .cumara, crop, pulverise the surface soil as much as possible without disturbing the subsoil, so that (here is a firm bed on which the .plants can produce their tubers. The depth to which to loosen the sou is about nine inches. .When preparing the ground for tin* crop do not incorporate any stable manure ■with the soil. Such a course would make the soil too rich, with the result that the plants would make a luxuriant growth of herbage with no corresponding increase of tubers. This should be guarded against at all costs. Manuring the Crop. The kumara crop is one which requires to be judiciously manured. It demands only a very moderate degree of richness and any great variation either above or below this will almost surely effect a decrease in the crop. As this is the opposite of what is desired, the gardener •will certainly take pains to prevent it. The success or otherwise of any application of artificial manure depends on the degree to which the soil may be enriched with the correct manure without inducing a rank growth of top. This will have to be found by experiment by varying the application from year to vear. I would advise the grower to commence at the bottom and increase the amount applied each year, rather than risk the crops for perhaps several years before the application was reduced sufficiently. Potash and Super for Kumaras. Whereas stable manure supplies the nitrogen that is required by crops such as cabbage, lettuce, etc., to stimulate the growth of herbage, such manure does not satisfy the food requirements of crops such as kumaras, as the " crop " fart of these plants is net the herbage, nt the swollen underground stems (tubers), that grow like roots. It has been found that this crop likes potash and phosphate, and a very small amount of nitrogen. These demands are supplied by a mixture of one part of each of sulphate of potash and" superphosphate and a-qnarter part of nitrate of soda, applied at the rate of one ounce to the square yard. This may be given before planting, or as liquid manure later on. I have obtained good results also from a light application of blood and bone, but I consider the former mixture to be safer. Raising the Plants. The plants should be raised on a hotbed if possible, by planting tubers thereon. These will produce shoots which, when about six inches long and posessing some roots, are pulled off and heeled in before planting, to harden them off and allow them to increase their root systems. Plants, which have been raised by the above method as advised in August, will be ready for planting ont any time now, providing, of course, that they have been hardened off. It there is no hotbed on which to raise the plants the next best thing i? to prepare a semblance of one in the ground. Excavate a pit and place in ifc beating material prepared as for the hotbed, and cover with four inches of soil. In this bed the tubers may be planted. Selection of Tubers. The selection of tubers for raising plants should be made carefully. Tubers of the best shape, with the fewest deep hollows and twists should be given preference. Small tubers with a lot of eyes should not bo used as the resultant shoots will be spindly owing to the overcrowding. If the gardener is unable to grow his own plants he may procure them from any seedsman. Planting Out Kumaras. The kumara crop usually follows the tiarly crop of potatoes and consequently the time of planting depends on the time of lifting the potato crop. This is usually about November or December. If planted later than December they do not produce very heavily. The best results are obtained" by planting early on in November. There are two ways of planting both of which will serve the purpose. The first method which is fairly common, is to draw ap ridges on which to set the plants. If it is intended to employ this method the ground should be prepared shallower or else there may bo too great a depth of loose soil after it has been made up into ridges. The second way is to plant straight, on to the flat surface of the ground. Distance Apart. When the method is decided upon proceed with the planting without- delay. Set the plants 18 to 21in. apart in rows about 30in. apart. Do not make the mistake of setting the young plants in an upright position as this greatly hinders production. Moreover, as the kumara lias a tendency to draw down deeper, the plants should be set very shallow. This is another reason for setting the plants in a sloping position, having all the ■plants sloping in the one direction. Subsequent Attention. The plants will spread a good deal Over the surface when making growth, and the tendency will be to root at the nodes. This is harmful to the crop and should be prevented by lifting the spreading stems every now and then. Other attention consists of hoeing between the rows to keep weeds in check. This crop £jpequt>fes very little looking after during

its growth, and usually the above would be ail the attention necessary. If not given when preparing the ground the application of sulphate of potash, superphosphate and nitrate of soda may be given any time by spreading it over the surface and hoeing it under or by making it into a liquid manure. Harvesting the Crop. On the average the crop requires four or five months in which to mature. The tubers should be dug when mature in the autumn but they should not be allowed to remain in the ground until the cold, wet weather commences or else they begin to deteriorate. The tubers should be lifted when the ground is dry as then the earth does not stick to them as it does if they are dug while the soil is wet. The tubers should be stored in a cool, dry place. For this purpose I use a barrel of dry, fine eartli and can recommend this method. One must be certain. however, that the soil is absolutely dry or else the stored tubers will commence growth and become useless. Soil intended for this purpose should be saved in the summer and thoroughly dried in the sun. It should be kent under cover until required for use. The same soil may be used year after year. Sand will serve the purpose equally well. Storing Kumaras. The method of storing is as follows■ Place a layer of soil (or sand) in the bottom of the barrel and then a layer of tubers, and so on, alternately soil and tubers' until all are stored, with, of course, a layer of soil on the top. The barrel should be safely covered to keep rats out. These vermin have a greatliking for kumaras and will do extensive damage if not prevented. There are various other methods of storing which gardeners employ in storing their crops but I will not enlarge on them here. The method of storing which must not be followed is to place them in a heap and cover with a sack. The tubers will sweat badly if stored in this manner will rot. Also, do not store the tubers while they are warm. Often, after digging them, they are left lying in the sun and they become quite warm; If stored in this state they will rot. Instead they should be spread out over the floor of the shed overnight and allowed to cool down. They will be cooled sufficiently by the morning to be stored in safety. ___________