ONION-CULTURE.

New Zealand Journal of Agriculture, Volume XIII, Issue 4, 20 October 1916, Page 281

ONION-CULTURE.

W. H. TAYLOR,

Manager, Arataki Horticultural Station

Onions can be successfully grown on various classes of soil, but it is essential that the soil be of a nature that will not readily bind under hot sunshine nor run together with heavy rains. It must be well drained, and worked to a depth of at least 18 in. Upland pasture land, drained swamp land, rich river-flats or loamy plains, all alike are suitable. The condition required is a soil that can be readily worked to a fine surface, and that will rem ain porous under all conditions of weather.

Though there are many varieties of onions, they may be broadly divided into three classes: (i) The giant kinds, (2) keepers of moderate size, and (3) eirly-maturing kinds. Pickling - varieties may be added, though the pickling - quality is largely a matter of cultivation.

The giant kinds are, as a rule, . successfully dealt with only by sowing .in autumn, ' although if sown in spring they are likely ..to develop comparatively large bulbs. : They are really not to be relied on to bulb at all; it is largely a matter of weather. The ideal season for onions would be a gentle spring with a fair rainfall, a fair amount of rain till the middle of January, and a dry autumn. A dry summer and wet autumn is bad for onions ; rain at that time excites growth and mars the keeping-properties of the bulbs. In the case of large kinds sown in spring, unseasonable rain would probably prevent them bulbing. Large bulbs require a lengthy period : for growth, and this is only obtained by sowing in autumn. Sowing too early, however, is dangerous. There is a time in every district that is best, but just when that time is requires some local experience to define. If the seed is put in too late there will be insufficient growth made by planting-time ; if sown too early there will be too much growth. To use an expression common to the horticultural craft, there will be “ too much autumn ” in them, and the majority will bolt to seed and be utterly worthless. Autumn-sown onions must be transplanted ; if this is not done many of them will run to seed, and those that do not. will never have any keeping-qualities.

In some districts it is rare to get really good bulbs from springsown seed. The principal reason for this is frequency of attack by mildew. In these circumstances autumn sowing of keeping-

varieties is frequently resorted to, as ■ large bulbs can be secured by that means, the reason being that bulbs are usually fully grown before mildew intervenes, which is seldom till after midsummer. It is well, however, to repeat that these bulbs are rarely good keepers, but provide good samples for early sale or home use.

The time to sow in the Wellington Province, or the middle district, is the last week in March or the first week' in April. Probably three weeks earlier is best in the colder parts of the South' Island. The time for spring sowing varies to a greater extent, being ruled by the condition of the soil as affected by rain. In the immediate precincts of Wellington spring rains do not prevent early sowing. Similarly, where the soil is porous to a considerable depth other districts are not affected. Early in July is the best possible time in such places. Where the seed can be got in at this time the crop is very unlikely to be prejudicially affected by mildew, for the crop will be practically matured when mildew appears.

It is, however, useless to sow the seed unless experience teaches that the soil will remain in a condition favourable to growth, a condition not present on flat lands with a heavy subsoil. In such places seed-sowing must be delayed till the sun gains more power; in some places it is necessarily delayed till the first week in September. The quality of the crop is then to a large extent dependent on autumn weather and the occurrence or ,non-occurrence of mildew. The bulbs from such late sowing are usually of medium or below medium size.

Mildew can be controlled only by spraying before the disease appears. It is possible to ward it off, but it is not possible to prevent loss if it attacks the plants. The remedy I have experience of is Bordeaux mixture, of which it is not safe to apply a. greater strength than 2-2-40.

PREPARING THE SOIL

Whatever the means the soil is prepared by, it should be donesome weeks before sowing or planting. It is not always possible to do this, and in such cases extra labour at sowing or planting time is necessary in order to ensure a good bed. The soil should be well worked, all lumps broken up by disk harrows, good use madeof the tine harrows, and the surface well rolled. A clod-crusher made of a heavy slab cut from a tree, with one surface flat, or made of. lapped boards, is very useful for breaking the surface to a fine tilth and for making an even surface. Garden plots are,, of course, dug with spade or fork. After raking the ground

level, tread the whole surface down firm with the feet. Never attempt to work the soil when it sticks to the tools or implements..

SOWING THE SEED.

In gardens the drills may be 12 in. apart —just leaving room for the hoe. With large lots more space is required so as to give room for a Planet Junior or similar machine; 15 in. is sufficient. For garden lots make the drills with either the corner of a rake (not a hoe), or with a marker made for the purpose. The drills must be just deep enough to allow of covering the seedno more. Cover the seed by straddling the drill, and drag the soil in with the heels of your boots. This is as quick as raking, and ensures perfect and even covering. After covering in, lightly rake in the direction opposite to that in which the drills runacross the drills, in fact. This prevents water settling in the drills. The Planet Junior has an attachment which marks the line for each drill at any distance apart which it may be set for. The machine makes the drills, sows the seed, and covers it in. Finish by turning a set of light harrows on their back and drawing them over. The quantity of seed to sow is 3| lb. per acre, but i| lb. to 2 lb. is enough 'to allow per acre when transplanting is to be adopted.

AFTER-CULTIV ATON.

The surface soil must be kept open by the means suitable to the extent of the work. Weeds must be kept out, and a certain amount 'of hand-hoeing is necessary along the lines. Thinning should be done early; in the field a large amount of it can be done with a sharp hoe in skilful hands. It is important that extreme care be exercised in setting the machine, so that the seed be not sown too thickly, as this factor largely rules the amount of labour . involved in thinning, which would be formidable - unless due care was taken in the manner indicated. Unless the plants are evenly spaced the size of the bulbs will be very uneven. Plants may stand 3 in. to 4 in. apart, and need not be in single file.

PLANTING AUTUMN-SOWN SETS.

This may appear to be a formidable undertaking. It largely depends on the inventive powers of the planter, and also on the speed of the workmen. Drills should be made with a marker. The sets should be dropped by one workman and fixed by another. The plants need not stand up. Merely lay them on their side and place a little soil over the roots, making it somewhat firm. The plants will soon assume an erect position. Plant keeping

kinds 4 in. apart, and large varieties 6 in. or more, according to the size of bulb required. In gardens where large bulbs are required they should be 12 in. apart, but a less distance for market work.

The amount of labour involved in planting is more apparent than real. It is largely set off by after-ease in cultivationno thinning and far less weeding. Moreover, the crop matures earlier than those from spring seeling. The bulbs being early on the market find a more ready sale. I have no hesitation in saying, from my reading and experience, that at least in places where an early spring start is not to be had the planting system would prove the more profitable.

MANURES AND FERTILIZERS.

Wood-ashes are of great value, not as fertilizers only, but as a help in keeping the soil open. They should be applied liberally during final prepartion of the surface.

Stable and farmyard manure, when it can be obtained, should be applied at first ploughing at the rate of 15 to 20 tons per acre. Soot acts as a fertilizer and insecticide. Apply just before sowing, sufficient to show over the whole surface. Superphosphate and bonedust can be used at the rate of 1 oz. each per square yard, equal to 2| cwt. per acre. Sulphate of potash may be applied at half the latter quantity. These fertilizers should be applied some time before planting. With nitrate of soda, two applications each of J oz per square yard should be giventhe first when growth begins, the second some time later, when growth is well established. The nitrate should be sprinkled along the rows of plants, preferably when light rain is falling.

PICKLING-ONIONS.

These are obtained by sowing thickly on poor soil about the middle of November. The plants are not to be thinned, and the soil should be of a free character, made very

VARIETIES RECOMMENDED.

Large kinds : Ailsa Craig, Prizetaker, Cranston’s Excelsior. Keeping kinds: Brown Spanish, James Keeping, Golden Globe,

Spanish Silver Globe. For quick bulbing: Silver King, White Italian Tripoli, Extra Early Barletta—suitable for hot climates. These do not keep, but bulb very early, and are excellent for early market work, particularly if sown in autumn and transplanted. For pickling : The Queen, Silver-skinned.