Problem Soils and their Treatment in Home Gardens

New Zealand Journal of Agriculture, Volume 90, Issue 1, 15 January 1955, Page 65

Problem Soils and their Treatment in Home Gardens

PROBLEM soils and their treatment in home gardens and work in the Vegetable garden in February are discussed in this article by A. G. Kennelly, Horticultural Instructor, Department of Agriculture, Dunedin. February is usually one of the most rewarding months in the home garden. Few gardens lack vegetables then, but if the growth of vegetables is good, so too is weed growth. Apart from making sowings and plantings which will develop during favourable autumn weather, the most important job in most gardens is to destroy weeds that, if left, will suppress any but the most vigorous or mature crop plants. As many weeds produce seed in February, they are likely to re-infest the ground with seed, which may be a source of trouble throughout the year. Many weeds are alternate hosts for pests and diseases and help to carry them over from one season to the next.

SOIL must be in good condition for the satisfactory growth of most vegetable crops, but the soils in many of the older home gardens and also in many of the newer housing areas are very poor. The soils in the newer areas usually contain fewer plant diseases, but in many instances they are not primarily horticultural soils; that is, before subdivision they, wereunsuited to the commercial production of vegetable crops and such crops can be grown on them satisfactorily only if they are. improved by' such factors as water, shelter, drainage, fertilisers, and organic matter. Organic matter, which is usually the most important factor, is the decayed animal and vegetable matter which gives soils their dark colour and it is the key to the fertility of garden, soils. It is being lost continuously in most home gardens owing to various breaking down agencies, fermentations due to fungi and bacteria working in linked progressions, oxidation due to exposure of the soil particles to the: sun and air in repeated cultivations, and to the leaching of rain and wind. Many of the older home garden soils -j that have been cropped for perhaps

15 to 20 years or more are in poor condition for growing vegetable crops, mainly because of lack of organic matter, as relatively little has been done to maintain or increase the amount in them. Too often the sole improvement measures ' have been the addition of mineral fertilisers such as sulphate of ammonia or relatively light applications of organic manures such as blood and bone. Green manure crops would do much toward building up the organic content of these soils. Soil Improvement The solution to the problem of improving the more intractable clay soils or excessively light soils and the older worked-out soils is the addition of organic matter such as farmyard manure, straw, compost, rotted sawdust, leafmould, seaweed, and rotted stack bottom, and the digging in of mature green crops. . The mechanical condition of sticky clays can in addition usually be improved to some extent by adding gritty material such as sand, which tends to improve drainage and aeration and make soils more open and

amenable to cultivation, but a large amount is needed to alter the texture of the soil of even a moderate sized garden. In most districts sawdust is the cheapest and most readily available source of organic matter, but if it is to be used in quantity it should be rotted before it is applied to the land. On areas that are not too exposed sawdust can be used as a mulch up to about 3in. thick, defending on whether there are plants in the area and their size. If too much unrotted sawdust is dug into ground that is to be cropped immediately, plants may suffer from nitrogen starvation and become pale and weak. Such plants, usually recover if kept well watered and fed at weekly intervals with sulphate of ammonia at about loz. to 2 gallons of water. For best , results in adding organic matter containing much fibre to the soil it is advisable to apply additional nitrogen in the form of sulphate of ammonia, as the carbon to nitrogen ratio of such fibrous material is usually too high for its most efficient utilisation. - Soils can also be improved if green or cover crops are dug in regularly, but such crops . should be bulky. In heavy soils particularly, they should be grown until they contain a great deal of. fibrous matter which when dug into the soil will not readily be dissipated but will combine gradually over a period with the gritty and

colloidal matter in the soil and form soil crumbs. In many of the smaller home gardens the need for producing vegetables continuously makes it difficult, if not impossible, to maintain the soils in good physical condition and it is in these gardens that for the best results it is imperative that additional organic matter is added to the soil each year. Successful commercial gardeners are aware of the need to maintain the physical condition of their soils. Commercial growers who cultivate small areas intensively almost invariably make heavy applications of organic manure for every second crop besides growing green crops whenever possible. On the larger areas the physical condition of the soil is usually maintained by frequent heavy green cropping. Alternatively on the larger holdings areas are sown rotationally, in grass. With a grass cover the soil surface is protected from the erosive effects of sun, wind, and rain and a thick mass of roots permeates the top 18in. to 24in. of soil, retarding the leaching of important plant food elements by absorption and effecting an improvement in the physical condition of the' soil by building up organic matter. Improvement of Cultivation Surface cultivation to destroy weeds is very important during February and in general a tool such as a push hoe that has a sharp blade that skims just below the soil is better than a tool such as a cultivator that relies on teeth for weed killing. The toothed or tined cultivator or chop hoe is .of value where the weeds are large or the ground surface rough. The hoe is one of the most useful garden tools and for most effective weedkilling full use should be made of

it on hot days when soil conditions are dry. It does not matter greatly in the smaller home gardens whether a push hoe or swan-necked or chop hoe is used, but the hoe should be clean and sharp. A few strokes of a

sharp file is enough, if given regularly, to keep even the hard-worked hoe sharp. On the push hoe only the cutting edge which lies uppermost when the hoe is being used and on the chop or swan-necked hoe only

the edge of the surface which faces the operator should be filed or ground (see lower left and lower right diagrams on page 70). It is desirable in any but the smallest of gardens to have both types of hoe. The push hoe is specially useful for cultivating between closely planted rows of vegetables such as onions, carrots, beets, and radishes. If it is sharp and wide enough and the blade is held at the correct angle, small weeds can be cut in one sweep simply by pushing the hoe along between the rows. The chop hoe is useful for rough ground where drastic action is necessary and for big weeds or for scraping off weeds on firm, level soil. It is of some value in loosening soil between rows in heavy ground that has become excessively compacted by being walked on, but it is not as useful for that as is the tined cultivator (upper left diagram on page 70), which is particularly useful for loosening soil between rows of crop plants. The value of surface cultivation in improving plant growth is one of the most controversial aspects of vegetable production. Gardeners of 20 or even 10 years ago were almost unanimous that cultivation or loosening the top 2in. to about 4in. of surface soil between crop plants—quite apart from cultivation for weed killingwas beneficial to all garden crops. The theory broadly was that a blanket of loosened soil acted as a mulch and was of great value, as it reduced capillary movement and evaporation of moisture, improved aeration and nutrition, and raised soil temperatures. The theory is now less widely held, as researchers have shown that increases in aeration, soil temperatures, and soil moisture compared with conditions in uncultivated soils are at

best very small and in many instances non-existent. The value of the soil mulch type of cultivation depends largely on the soil and the kind of crop grown. Plants with very small root systems such as celery, beetroot, and onions are more likely to benefit from it than plants with stronger and more widely spread root systems.

Work for February

Though there is some variation according to district and situation in general there are only four good growing months after Christmas and with the disruption in garden work so often caused by the Christmas and New Year holidays many gardens are neglected during the greater part of January and important garden work is left until Febru-

ary. This loss of one of the best growing months may seriously reduce the period for good growth in southern districts, particularly of the winter greens which include leeks, savoy cabbage, winter cauliflower (broccoli), and silver beet. Winter greens should be regarded by home gardeners as among the most important crops in the garden, as with forethought they can be grown so that produce can be harvested from them from late autumn through winter until late spring, when vegetables are most likely to be scarce and dear. As it is late in southern districts and the less favourably situated gardens elsewhere for the setting out of winter greens, they should be planted without delay if this work has not yet been done. Success apart from weather will depend largely on soil fertility and the use of healthy well-grown plants. Beetroot In most districts February provides the final opportunity for sowing beet-

root to mature before winter. There are several types of beetroot, flat or turnip-rooted, globe (round), intermediate, half-long (obelisk) or z stumprooted, and long. In most northern districts February sowings usually produce good crops if the situation is favourable and soil conditions are good, but in districts where autumn temperatures fall more quickly and frosts are earlier seed should be sown in favourable situations not later than the beginning of February and a quick maturing, flat or turniprooted variety should be chosen. Beetroot seed germinates in a wide range of soil temperatures, though if low temperatures are experienced before plants are well developed they may produce seed stalks instead of swelling the root further. Quality beetroot can be produced only by rapid growth, which in turn is largely dependent on soil fertility. In particular the nitrogen in the roots is in direct proportion to the amount supplied in the soil, and soils that produce the largest yields also produce plants that have the largest proportion of water to dry matter and so are most succulent. Beetroot requires a sunny open situation, as it rarely thrives if shaded, even if soil conditions are otherwise perfect. Soil and manurial requirements are similar to those for Carrots. Seed should be sown £in. deep, about 10 to 15 seeds to the running foot, in rows 12 to 15in. apart. Plants should be thinned to 2in. to 3in. apart as soon as they can be handled. Carrots A late sowing of an early variety of carrots can be made in the warmer districts in February. Late sowings are sometimes less subject to the attack of the carrot aphis and the carrot rust fly and are therefore preferred in some districts. In southern districts the situation and autumn weather must be favourable and the seed should be sown without delay in soil that is in good condition and worked to a fine tilth. 1

Many home gardeners have difficulty in growing carrots, though in most gardens carrots, should be one of the most productive and important crops, as they can be used at various stages of maturity and if sowings are suitably spread, they should be available in most good-sized gardens during most of the year. The food value of the carrot is high and its vitamin content important in nutrition. Carrots are not difficult to grow, but soil must be friable, moist, and well drained, and the plants must be kept free from insect pests. Light sandy loams produce the smoothest and straightest carrots, but all good loams apart from the heavier clay loams can be improved to produce satisfactory crops. Peat soils are usually highly productive. Difficulty is commonly experienced by home gardeners in growing carrots in the older, sometimes rather light soils that have been worked for many years without having had much organic matter such as compost or farmyard manure applied to them. Trouble is commonest in the smaller garden where cropping is usually continuous and good crop rotation with adequate green cropping is difficult. Carrots grow well in soils that were heavily dressed with organic manure for the previous crop. The application of heavy dressings of organic manure just before sowing is not advised, though results may be satisfactory if the manure is well rotted and mixed throughout the root area. The incorporation of lumpy masses of fresh or only partly rotted manure is especially to be avoided, as local conditions may become highly acid and the carrots coming in contact with the manure may become forked or distorted. Soil Preparation Soil preparation for the seed-bed should be thorough. Lumpy soil should be pulverised until a fine tilth is obtained. Results are likely to be better on most soils if mineral fertiliser is used

to supplement the organic manure in the soil. A complete fertiliserone made up of nitrogen, phosphate, and potash—is likely to give best results on most soils, but good responses are obtained on many New Zealand soils from superphosphate alone. Superphosphate can be worked in at the rate of about 2oz. to 3oz. to the square yard during the final cultivation.

Carrot seed is rather small and should be sown only |in. deep in rows 12in. to 15in. apart at the rate of about 15 to 20 seeds to each running foot of row. On soils that tend to form a crust after rain the soil over the seed should be kept hoed to break the crust and to facilitate the emergence of the tiny seed shoots. Control of Aphides Aphides or green fly are commonly the most troublesome pests on carrots, and home gardeners sometimes have difficulty in detecting them. The plants should be examined regularly from the seedling stage so that spraying can be begun as soon as the aphides appear. Usually the first and most readily noticeable sign of aphides is the presence on the carrot foliage of tiny whitish or greyish flecks rather like cigarette ash which are the castoff skins of the aphides. If the plants are young, the presence of just a few aphides soon saps their vigour and in warm weather the leaves even of large plants quickly lose turgidity and if infestation is heavy, the plants become flaccid and growth may cease.

Aphides can be controlled by spraying on a warm still day with nicotine sulphate 1 fl. oz. (approximately 7 teaspoons) to 5 gallons of water, plus a little soap or lime to activate the nicotine. Alternatively, H.E.T.P. can be used at the same strength but without soap or lime. .' Cucumbers In most districts cucumber vines should be in bearing in February. The cucumber grows quickly in warm conditions if the soil is in a fertile and friable condition. Soil temperature is very important, as cucumber plants make little growth at soil temperatures below 50 degrees F. and a higher temperature is desirable. Light soils that have been well mulched or have had plenty of organic matter worked into them are excellent for cucumbers if moisture is adequate and drainage is good.

Cucumbers are more tender than tomatoes or sweet corn and as the leaves are readily scorched by sun or wind in exposed situations, they should be grown between rows of taller plants such as peas or sweet corn which will provide some shelter. Cucumbers are usually grown either in hills or groups of several plants set fairly closely together, in single rows, or in large gardens occasionally in double rows. The shoots should be trained to facilitate access to the plants. Only shallow hoeing around vines should now be necessary and if this is done regularly, weeds will be destroyed when they are small.

Except where the soil is very fertile the yield of cucumber plants is usually improved by a topdressing of sulphate of ammonia or blood and bone or where conditions are dry by applications of liquid manure, which can be made from animal manure or sulphate

of ammonia at loz. dissolved in about 2 gallons of water. Celery Though it is useful for soups and stews, celery is most popular as a salad vegetable. Most home gardeners like to set out plants as early as possible and though plants can be set out earlier where temperatures are high enough, December and January are the preferred months for planting. Later planting is only practical where autumns are mild. Home gardeners sometimes defer planting until after the holidays so as to be able to attend to the plants throughout their growing period, because for good growth celery should have a continuous and fairly high supply of moisture and also, because in most districts regular spraying is necessary to keep the plants free from leaf diseases. However, temperatures are of first importance and if they are not high enough, plants will fail.

. Home gardeners usually buy young celery plants from seedsmen or nurserymen, as the seedlings of selfblanching celery need to be raised in consistently higher temperatures than prevail in most districts without the aid of a glasshouse or heated frame,

Varieties of self-blanching celery differ according to their heredity, but with most varieties seed stalk development is initiated if they are subjected for a week or more to temperatures of from 35 to 50 degrees F. Manures Though celery is more tolerant of insufficiencies of moisture, nutrients, light, and space than it is of low temperatures, a good deal of skill is needed to grow self-blanching celery well, as it needs a rich soil, ample moisture, and good drainage. Organic manure such as farmyard manure or organic fertilisers such as blood and bone are preferred, but where organic manures are not available in sufficient quantity it is usual to supplement them with mineral fertilisers. Nitrogen and phosphates are usually applied and give improved growth on most soils. Potash is less often applied, though it is probable that it would improve . quality on many soils.

A complete and balanced fertiliser made up of 2-| parts of sulphate of ammonia, 2| parts of superphosphate, and 1 part of sulphate of potash applied at about 2oz. to 4oz. to the square yard according to soil fertility should promote good growth.

Manure should be mixed into the top few inches of the soil before the plants are set out; deep placement is not advisable, as the roots of celery remain near the surface. Soil moisture is as important as soil nutrients in the growing of self-blanching celery, and to facilitate watering in soils that may dry out plants can be grown in shallow trenches. XT 14- x. x- ™ on-self-blanching Types The older types of celery which are not self-blanching are usually considered less difficult to grow than the self-blanching types and are considered by many to have a superior flavour and texture. A well-grown ?o e hdlv°of laiffe y thffik U flesh be d ’Xenleffi lea/stalks 1 and’the charStenstic nuttv -X™ flavour th Thnuld h J stron 01V deveioned aVOUr should be stron ■qi .. ’ • , , . ~. . Flaming m a trench is specially favoured by those who blanch the older n -self-blanching varieties by moulding the earth up the stems, but it is practicable only where the soil is deep and well drained and does not QaW hn ?v. ct rau , cb organic matter, to' leaf snot; diseas? than blanching kind Where the disease is nrevalent nlants should he snraved with 1 a copper fungicide such as Bordeaux mixture or Conner oxv! chloride at intervals of about 7 tn 14 days' Control of the disease mav be obtained with less frequent spraying where humidity is low or a good coverage of snrav residue remains on plfnts for a fairly longtime me pianis lor a rainy long time. Lettuces ~. , ' During the warmer part of the year lettuce is grown in practically all home -gardens and with seasonal sowmg or . planting it can be grown in most districts to be available throughout the year. Lettuce is a crop that

must be grown quickly if the leaves are. to be crisp. Slow growth or checks to growth cause the flavour to be bitter and though varieties of lettuce have been developed that have considerable tolerance to hot weather, high-quality lettuce can be produced consistently only where the temperature of the soil and the air is moderately cool while the crop is maturing. Fluctuating high and low temperatures do not promote good growth. With most varieties very high temperatures favour early seed head development, bitter flavour, and poor hearts. Lettuce sown even early in February is unlikely to develop good heads before winter in southern districts or in unfavourable situations elsewhere unless soil conditions are very good. Lettuce matures in from about 2 to 5 months according to growing conditions and varieties, but conditions have to be exceptionally favourable to produce good lettuces in 2 months. It is not advisable unless lettuce is in considerable demand to make large sowings which may not mature until so late in the season that heavy frosts can be expected. Though lettuce will tolerate fairly heavy frost, if it is severely frosted at or near maturity, the outer leaves become damaged and the plants subject to slimy rotting. Maturing plants will grow very little during continuous frosty weather and though the heads may become solid, they will remain small and may suffer injury that makes them wasteful in preparation for the table. In February planting rather than sowing will therefore be advisable in many districts. . Manuring The root system of lettuce is relatively shallow and though excess water is not desirable, plants should be set out in a moist soil that does not dry out. Practically all soils are

improved for lettuce growing by the addition of organic matter. The amount needed varies with the soil type. Loss of organic matter owing to decomposition is rapid in light soils, but heavy soils also need organic matter, as it improves aeration and water movement. Well-rotted farmyard manure gives excellent results, but very heavy dressings, particularly when the weather is most favourable for growth, may result in loose heads. Where • sufficient farmyard manure, compost, or similar material cannot be obtained soil can be improved by growing a green manure crop and digging it in early enough for it to rot down before the lettuce is set out. Unless rotting is fairly complete before the plants are set out growth may be checked through depletion of the nitrogen in the soil by the bacteria that cause decomposition. On very heavy soils where the danger of depletion of the nitrogen supply may be outweighed by the advantage of improving the physical condition of the soil it may be advisable to allow the green crop to mature fully before digging it in so that it contains much fibre which when incorporated into the soil is likely to be effective for a longer period. If additional fertiliser is needed, blood and bone is likely to give good results on most soils. Alternatively a complete mineral fertiliser can be made up by mixing 2| parts of sulphate of ammonia, 2| parts of superphosphate, and 1 part of sulphate of potash. The complete fertiliser is much more concentrated than blood and bone and it can be applied at about half the rate of blood and bone. Rates of application vary from about 2oz. to 6oz. to the square yard according to the fertiliser and the fertility of the soil. In home gardens nitrogen

is usually the limiting element in growth of lettuce. However, too much nitrogen may result in poor hearts and loose leaves. Soil should be worked to a fine tilth for sowing, as lettuce seed is small and germination relatively weak. Seeds should be sown thinly (as the first thinning should leave plants about 6in. apart) about -4-in. deep in rows 12in. to 15in. apart. Popular varieties include Webbs Wonderful and Imperial 615. Peas Garden peas can still be sown in the north, though in most southern districts it is rather late for peas sown even early in February to mature before winter. Except in the warmer districts sowing should be confined to sheltered situations lying well to the sun and where the soil is well drained and in good condition. An early or quick maturing variety should be chosen. In favourable northern districts early maturing peas can be sown usually until about the middle of the month, but in general early sowing is recommended. Peas are hardy and grow well in cool, but not cold, weather. They are one of the best crops for soil improvement, as they leave a considerable weight of organic matter in the soil that is specially valuable because of the nitrogen gathered from the air which the peas fix in the nodules of their roots. One contributory factor to the failure which sometimes occurs when peas are grown for the first time on some of the drier soils that lack organic matter is an insufficiency of the nitrogen-fixing bacteria needed by them. Garden peas grow in association with the same kind of nitrogenfixing bacteria as broad beans, lentils, sweet peas, and field peas. Manures In good soils peas do not need heavy fertiliser dressings ' and commercially, both in New Zealand and overseas, a very moderate dressing of superphosphate alone has given good results on a wide range of soils. Garden peas are fairly tolerant of soil acidity and usually grow well in fairly acid soils, but moderate applications of lime, about 3oz. to 4oz. to the square yard, are advisable on the more acid soils. Injury often results where fertiliser is applied in the drills with the seed. It is best applied to the soil 2in. to 3in. on either side of the seed row or at least lin. under the seed. The fertiliser can be applied in a drill taken out with a hoe and partly filled in before the seed is sown. Peas require well-drained, fertile soil and in any but the most ■ fertile soils they repay soil improvement measures. Deep digging of heavy soils and the incorporation throughout the soil area of moderate quantities of well-rotted organic matter are advised. Surface or nearsurface applications are not only liable to cause seed injury but may encourage shallow rooting, which is specially to be avoided where conditions are liable to become dry. A supply of nitrogen in the soil helps young plants to become established, but most soils that have been kept in good condition by regular dressings of well-rotted organic matter should be adequately supplied and on most home garden soils superphosphate alone at loz. to 3oz. to the

square yard is likely to give satisfactory results. Seed Sowing Seed can be sown at about 10 to 15 seeds per running foot, in drills taken out with the corner of the blade of a chop hoe, or a broad drill can be formed with the chop hoe or spade and the peas sown lin. to 2in. apart throughout it. Seeds should be sown about lin. deep except in the lighter soils that dry out readily, where it can be covered to a depth of ljin. to 2in. If the drills are taken out a little deeper, when part of the covering soil is put back the hollow left will serve to mark the row and facilitate watering. Later the peas can be earthed up to keep the roots cooler and in windy conditions to hold the plants more firmly. For dwarf varieties rows should be at least 18in. apart. William Massey is one of the best varieties for sowing in February. Pea crops coming into bearing should be watered if conditions are dry. On soils that dry out quickly a mulch of lawn clippings or similar material may be of value. Though peas grow best in moist, well-drained soil it is not usually advisable to water, the soil after sowing until the plants are well established, as germination losses are usually much heavier in wet soils. Mildews In the dry weather which is often experienced in February and March and when considerable differences in day and night temperatures may result in heavy dews, peas are sometimes attacked by powdery mildew, which can be recognised by £ greyish powdery

coating that rubs oft when plants are handled on leaves and other parts. The disease may cause yellowing or death . of the plants. Some control can usually be obtained by spraying or dusting with sulphur, but the disease is usually difficult to control when well estab- : lished and where conditions favour it, and except to check an infection in the early stages spraying or dusting is usually of limited value in the home garden. Diseased haulms should be burnt immediately after the crop has ‘ been picked to prevent infection of . subsequent crops. Downy mildew, which . differs from powdery mildew in that it occurs as a greyish-brown growth principally on the under surfaces of leaves and on pods, may also be troublesome. Diseased pods may contain spore masses instead of seed. '■ Downy mildew occurs chiefly in moist weather and though spraying is rarely necessary, copper fungicides such as Bordeaux mixture or copper oxychloride give fairly effective control. Diseased haulms should be burnt and crop rotation; practised. Collar Rot Collar rot is probably responsible for more losses in pea crops in home gardens than is any other trouble. It may be caused by one or more of at least three different organisms which are capable of remaining in the soil in a dormant state for 2 or 3 years even without a suitable host plant. Preventive measures are : very important and include the use ,of . clean unmarked , seed, dusting seed with organo-mercury or copper or nonmetallic seed dusts (which may he obtained from most seedsmen), burning diseased pea vines, and growing

crops only on well-drained land where long rotations can! be practised. Silver Beet and Spinach Beet Silver beet is also called Swiss chard or sea kale beet and good strains if well grown are particularly robust with strong rooting systems and large succulent leaves. Spinach beet or perpetual spinach beet produces more numerous leaves that are not as large as those of silver beet but can usually be plucked from the plant for a longer period. Both , silver beet and perpetual spinach beet are excellent as stand-by crops, particularly in the smaller home gardens, as in most conditions they bear for a longer period than any other greens. In addition, because of their vigour they succeed in most soils ■ and they are not usually affected by root diseases. Seed should be sown without delay in any but the most favourable districts to enable plants to make as much growth as possible before winter. . Alternatively in the cooler districts plants should be set out. They are usually available from seedsmen. Seed should be sown Jin. deep in rows 15in. to 18in. apart. Most of the listed varieties are good. Spring Cabbage Cabbage is one of the most valuable garden vegetables, as it is not only nutritious but grows well in a wide range of soils and in good conditions is one of the heaviest yielding crops. Though in northern districts or in sheltered situations spring cabbage can be grown from seed sown in March, February, is the preferred month for sowing. Where soil and situation are not good seed should be sown as soon after the end of January as possible. It is not usual to sow seed of spring cabbage before the end of January because if seedlings are set out too early, plants mature too

quickly. If seed is sown early and plants are left in the seed-bed until the usual setting out time, they may become too large to transplant well. Where winter temperatures are low and very large plants are set out they are specially liable to run to seed. Cabbage is a cool climate vegetable, but the seed germinates and the plants grow well in a fairly wide range of temperatures if the physical condition

of the soil is good and it contains adequate moisture and plant nutrients. Protective Sprays Many home gardeners have difficulty in raising cabbage seedlings for setting out for the spring crop. The seed usually germinates quickly, but seedlings are liable to be attacked by fungous diseases such as mildew and by insect pests such as caterpillars, aphides, or thrips. Regular spraying with Bordeaux mixture or copper oxychloride will control most fungous diseases and if a suitable insecticide is applied, insect pests can be controlled. Cabbage seedlings are difficult to spray because the leaves have a smooth, almost greasy surface which is difficult to wet. In the early stages, too, the leaves are rather delicate and easily depressed by the pressure of sprays. Proprietary wetting. agents, which are usually . compounds similar to detergents sold for household dish washing, aid the wetting of the leaves if added to the spray. If the spray is applied under pressure through a fine nozzle so that spray drifts as a mist, the under sides of most of the leaves should be covered with spray deposit. Caterpillars and usually thrips are readily controlled by spraying with D.D.T. It can be used alone or added to a fungicidal spray. Thrips often check young plants and little is done about them because they are not seen unless the plant is examined closely. Thrips are minute cigar-shaped creatures up to about Jin. long. They are dark in the adult stage and have wings, with which they fly short distances if disturbed. The immature stages are wingless, green or light yellow, and do not move readily. Thrips rasp the under surfaces of cabbage leaves and denude them of

their green colouring matter and so reduce the leaf function. : Aphides, usually the cabbage aphis, which is greyish and rather mealy,? may also attack cabbage plants. Among any group of grey aphides, particularly in dry conditions or toward the end of the season, a number are usually winged. Under dry conditions and in heavy infestations it is often possible if the colony is observed closely, to see tiny wasps not much larger than the aphides which parasitise the aphides. Aphides and to a great extent thrips can be controlled by spraying on a hot, still day with nicotine sulphate at 1 fl. oz. to 5 gallons of water (plus a little soap or lime to activate the nicotine). Alternatively H.E.T.P., which will also : give good control of thrips, can be used at the same strength but without soap or lime. Varieties Flower of Spring and Enfield Market are the most commonly grown varieties except in some of the northern districts of the North Island, where Jersey Wakefield ' and the summer '

cabbages Green Acre and Golden Acre are also favoured. : < Several other good varieties are listed in most catalogues, and for the home gardener . . who " has sufficient ground and is interested in v improving his crop a trial of a new variety is well worth while. It may specially suit his conditions and even if it is not an improvement, it may mature at a different period and contribute to the continuity of . his supply. Onions The onion is usually considered one of the most nutritive vegetables. In most districts the crop should now be mature or nearly so and as the . ripening and hardening of the bulbs are important factors in onion growing because of their effect in improving the keeping quality of the bulbs and making them more resistant to storage diseases, the onion bed should not now be watered, as wet conditions are likely to prolong leaf and root growth. The bed should be kept weed free. Strong weed growth harbours pests and diseases and reduces the efficiency

of sprays. It’ is important, if : the onions are to be kept, to avoid damage during lifting. A common practice among both commercial and home gardeners is to bend over the, tops of the nearly mature onions to hasten the dying down of the tops. Usually rows are paired with the tops pressed over and laid to the centres of the double rows. Though it gives the onion bed a tidy, workmanlike appearance it is unlikely, judging from experimental work, that this furthers the dying down of the tops; it is probable that it reduces yields slightly. If conditions in the field are unfavourable for drying, onions should be,harvested as soon as the tops are as dry as local conditions are likely to permit and final drying done by putting them on airy racks made of battens or laths or by spreading them out on wire netting in dry, well-ventilated shelter.

Many home gardeners trim off the tops of onions close to the. bulbs as they harvest them, though it is not essential and may even be a disadvantage, as the top tends to cushion the bulb during handling. If trimming is done, it is particularly important that the onions should be sheltered from the direct rays of the sun. They should be covered with the trimmed tops, as otherwise the bulbs are likely to suffer sunburn or sunscald. When bulbs are sunscalded the outer tissues become bleached and usually collapse and soft rot may follow. The green leaves of growing onions are liable during February to be attacked by thrips, which cause silvering of the foliage of onions by rasping the green colouring matter from the surface of the leaves. This reduces the power of the leaf to manufacture the substances which are essential to growth. Thrips can be controlled by spraying on hot, still days with nicotine sulphate 1 : 800 (1 fl. oz.) to 5 gallons of water plus a little soap or lime to activate the nicotine) or by spraying with H.E.T.P. or D.D.T. Shallots Shallots should now be mature in most gardens and can be harvested as soon as they are dry. The tops are not usually as large as those of onions and usually need not be trimmed, as they protect the bulbs in storage and retard, the progress of rots that may develop. Shallots are generally easier to grow than onions and deserve to be grown more widely, particularly on the horticulturally poorer soils. Their cultural requirements are' in general similar to those of the onion, but as they are not generally grown from seed but from off-shoots of the parent bulbs, they are much less- exacting in their needs. The off shoots, root readily if they are pressed on. to the soil and are more tolerant of adverse conditions than are young onions. The bulbs of the large-bulbed varieties of shallots are as large as the bulbs of some of the smaller-bulbed varieties of onions and few can distinguish between the ' flavour of shallots and that of onions. The bulbs of some varieties of shallots are very small and are well. suited to pickling, but they need more skinning and trimming in culinary use than do most varieties of onions. The smaller varieties of shallots have the merit of being particularly hardy, ■ succeeding - in adverse conditions and being very resistant, to storage .troubles. .