TOMATOES

In the sixteenth century the tomato was regarded with extreme suspicion — the well-known Elizabethan gardener, John Gerard, considered the entire plant to be ‘of a ranke and stinking savour’ and he had an equally poor opinion of its nutritional value. Today we think otherwise. Tomatoes are known to be rich in Vitamin C and they are grown by nearly all gardeners, either outdoors or in the greenhouse.

TOMATOES OUTDOORS. Tomatoes grown outdoors are very much of a gamble. In the north, most of the fruits must be picked green and ripened indoors. A wet, sunless summer, whether in the north or south, will seldom give a worth-while crop. In a really hot summer, results can be very good indeed in the south and Midlands.

Tomatoes need the maximum amount of sun possible and detest draughts. A south border is excellent, but they succeed equally well by a sunny wall or fence, and in pots or tubs. It is quite easy to grow satisfactory crops in rows across an allotment, but never attempt to cultivate them in partial shade.

Jerusalem artichokes can be grown as windbreaks behind tomato rows as they reach 10 ft.

Pot-grown seedlings or those started off in soil blocks make better plants and fruit earlier than tomatoes raised in boxes. As with seedlings generally, a well-grown specimen should be short and stocky, not tall and spindly. Be sure to obtain tomatoes that have been ‘hardened off’ for outdoor cultivation — otherwise you may be given plants which were intended only for growing indoors. Tomatoes flourish on most types of soils. If the ground is poor, apply humus in the form of material from the compost heap, well-decayed manure or hop manure.

A good supply of potash is essential for successful tomato growing. Potash enables the fruit to mature properly and improves both colour and sweetness. Sulphate of potash should be given to the ground before planting — muriate of potash, wood ashes or bonfire ashes are excellent alternatives. There is very little difference in yield between tomatoes grown on plots dressed with muriate of potash and others treated with the more familiar sulphate of potash.

The soil must be thoroughly watered before any planting is attempted. Late spring frosts are always a serious problem, and it is not generally advisable to plant out tomatoes until the first week of June, though late May planting may be safe in sheltered south or south-western districts. If night frost seems likely after planting (though in June this seldom occurs) cover the seedlings with paper or pots. Tomatoes must be planted moderately firmly, and the soils should come about 2 in. higher up the stem than it did in the pot in which the seedlings were originally grown. This helps to induce a fresh throw of surface roots from the base of the stem. Plant at least 18 in. apart and allow 3 ft. between the rows — the type known as ‘bush tomatoes’ require rather different treatment which will be described later. Staking must be done at planting time — use a 4 ft. stake for every plant — or a sudden gust of wind may dislodge the plants. Do not tie the stake too firmly to the stem, because a tomato stem expands fairly rapidly. After planting make sure that the surrounding soil is quite firm — loosened ground tends to encourage rank growth. Do not water until the plants are growing rapidly, unless the atmosphere becomes very dry.

Stopping of Tomatoes:

As soon as the plants begin to ‘grow away’, side shoots will form. These must be rubbed or pinched out directly they appear, for with the exception of the new dwarf and bush tomatoes, all varieties are best grown with one stem only.

Pinch out the growing point after three or four fruit trusses have formed — in cold, wet districts and in the north of England three should be regarded as the maximum and two will often be enough. With really good cultivation these limits may be exceeded by an additional truss in each case.

Watering of Tomatoes:

Once the plants are making rapid headway, they must be well watered during dry spells. As with all plants, watering should be thorough and occasional rather than little and often. One very useful method is to sink a flower pot into the soil and fill it with water — the plant will then be encouraged to travel downwards in search of moisture and not rise to the surface with consequent risk of burning (the tomato is a surface rooting plant). In dry areas such as East Anglia, where there is frequently very little rain throughout the summer, many gardeners give their tomatoes a permanent mulch. Partially decayed manure, peat, fresh straw, compost, or lawn mowings are all most effective — the last named should be free from weed seeds.

Feeding of Tomatoes:

Tomatoes should not be fed with inorganic fertilizers until the first truss has set. Application should only be made when the soil is moist. Any complete fertiliser with a high potash content may be used.

Setting of Tomato Fruits:

The first truss of fruits often fails to set properly, both outdoors and in the greenhouse. Hormone sprays containing bcta-napthoxy-acctic acid may be used to supplement natural pollination and to ensure uniformity in size, weight and ripening. The bottom trusses are sprayed when the majority of flowers are open, using an atomiser, small hand sprayer or syringe. Direct the spray upwards into the open flowers but avoid wetting the foliage and growing tip of the plant. This treatment produces seedless fruits but the taste and vitamin content are unaffected.

Choice of Varieties:. The following represents a small selection. Ailsa Craig, Blood Red, Early Dawn (very early), Essex Wonder, Histon Early, Histon Ideal, Hundredfold, Market King, Melville Castle, Quality Street, Stonor’s M.

P., Stonor’s Moneymaker, Sutton’s Leader. Individual varieties do not necessarily combine both early ripening and heavy cropping. Amateurs may find it advisable, particularly when gardening in the north, to concentrate on tomatoes notable for early ripening rather than on those with very heavy yields. Examples of the former are Harbinger and Market King. The variety Hundredfold is distinguished by both early ripening and heavy yields. Many gardeners prefer the flavour of the yellow varieties which are usually sweeter, though they may not crop as freely as the reds. Stonor’s Midday Sun, Baker’s All-Gold, Sutton’s Golden Queen and Yellow Perfection are recommended.

Bush Tomatoes:

The bush tomatoes have a low, spreading habit and vary somewhat in height. Since the fruit is often liable to rest on the soil, a mulch of straw or a wire should be employed where necessary, to raise up the tomatoes. Stonor’s Dwarf Gem was one of the first varieties. There are several ways of growing this; if left alone and not supported, it develops into a bushy plant as much as 3 ft. wide, with numerous side shoots. For extra early crops leave two main stems and remove all laterals — in this case space the plants 18 in. apart and allow about half a dozen fruit trusses. This plan I-s specially recommended for frame and cloche cultivation Yet another method is to stop the plants above the first truss, allow 4 — 6 laterals to develop and stop them at the first or second truss — in this instance not more than 2 ft. should be allowed between individual specimens. Dwarf Gem grows unusually freely and a constant watch must be kept for superfluous shoots, which must be removed at once. The plants should always be supported with short sticks or the weight of the fruit may bear the stems to the ground. Some disbudding is also necessary.

Amateur Improved is a new development in tomato breeding. It makes a sturdy, compact plant, 9—12 in. high with medium-sized fruits. Neither staking nor pinching out of side shoots is required, but straw, peat etc. must be placed underneath the plants to prevent mud splashes and to stop slugs eating the fruits. Amateur Improved is at least 14 days earlier than the ordinary varieties and has been known to yield I41/,, lbs. of ripe fruits per plant.

Atom starts to ripen its fruits about a week earlier. With good cultivation at least 20 fruits to the lb. or 125 per plant, may be expected. The plants cover a square about 15 in. on a side. The fruits are excellent for bottling.

Tomatoes under Cloches:

If tomatoes are grown with the aid of cloches, the gardener may overcome the vagaries of many English summers. When the plants are covered with cloches for a month or so after planting out (this can be done in mid-April if cloches are used) and similarly protected in early autumn, practically all the fruits will ripen satisfactorily outdoors.

Tomatoes can easily be grown throughout the season under cloches and should then ripen a month earlier than usual. If the barn type is used make a trench 6 in. deep to give additional space under the cloches. The plants must be grown at an angle of 45 degrees in order to prolong the period during which they can be left under the cloches. The special tomato cloches are excellent, since they allow one side to be taken away, and the plants receive considerably more air than with the older types. Raise the cloches as the tomatoes grow, on layers of soil (made as firm as possible) or on bricks. The rows should face south, west or south-west. Space the plants about 20 in. apart and remove all laterals except the lowest, so that two main stems are formed. Staking is essential. If you can only secure small cloches, they must be removed once the plants become too tall. Replace these cloches at the north side of the rows and continue to cultivate your tomatoes in the usual way. When two or three trusses of fruit have set, lay the plants down upon dry peat or straw, or support the trusses so that they do not actually touch the ground, and leave them to ripen.

Varieties especially suitable for cloche cultivation include Harbinger, Hundredfold, Market King, Stonor’s Moneymaker, Stonor’s Dwarf Gem and the Amateur.

Tomatoes in Cold Frames:

Tomatoes produce excellent crops in cold frames — for instance, January-sown turnips which will be ready for pulling by mid-May can be followed by tomatoes. Radishes, lettuces, onions, etc., sown from January to March may also be removed before the tomatoes are planted, and autumn-sown cauliflowers can easily succeed tomatoes. In this way you can make the fullest possible use of your frame and add a good crop of tomatoes to the total output. Stonor’s Dwarf Gem, treated as suggested for growing under cloches, is a suitable variety. To avoid plants pressing on the glass it is necessary to train them horizontally, either on stout string or on canes.

Diseases of Outdoor Tomatoes:

Blight. The most common disease among tomatoes grown outdoors. This trouble is similar to potato blight, and it is preferable, where space permits, not to grow tomatoes too near to potatoes. Tomato blight flourishes in warm, wet weather, appearing in July or August as black or dark brown blotches on leaf, stem and fruit. Spray your plants with a copper fungicide (which is also highly effective against potato blight) at the end of June, repeating every 14 days as necessary. The desirability of preventive spraying of outdoor tomatoes is shown by the fact that in an experiment carried out on 2 acres grown under identical conditions, the sprayed acre yielded 16 tons of sound fruit and the unsprayed acre only 2 >/2 tons of sound fruit. Always spray immediately before finally gathering all the green tomatoes at the end of the season. This will prevent blight developing when the tomatoes are ripened indoors.

Tomato Splitting. This condition is not caused by disease or pests. It is usually due to excessive moisture in the plant from heavy watering after dry weather. Splitting occurs perhaps more often with tomatoes grown against a wall, where the soil naturally dries out more easily. If the ground is light and dry, a mulch of peat, grass cuttings or any other source of humus will conserve moisture and help to prevent splitting. After a dry summer, early autumn rains frequently lead to bad splitting. At this stage when the plant is fully grown, splitting can often be controlled by making a horizontal cut about half way through the stem, near the base. If carefully done this checks the flow of sap and at the same time allows the plant to continue to develop slowly. Tomato Scald. This disorder is not very common, but is mentioned here as a warning against attempting to ripen tomato fruits by letting them touch the glass in a sunny window. Such a practice is sometimes liable to produce a wrinkled, white patch on the fruit — it will be shown later that temperature and not light is the chief factor in ripening tomatoes.

TOMATOES IN A COLD GREENHOUSE.

In unheated greenhouses it is quite easy to obtain earlier crops of tomatoes than outdoors, and since practically every fruit truss can be allowed to develop, a heavier yield is usually secured.

The least touch of frost is harmful to tomatoes; on no account plant out seedlings from the nursery until late April or the beginning of May — they should then be ready for picking from late July onwards. Tomatoes may be grown cither in prepared beds on the ground (spacing the plants 18 in. apart), or in 12 in. pots and boxes on greenhouse staging. Prepare the soil by incorporating potash as with outdoor tomatoes, adding some good loam and well decayed manure, if possible. It is extremely important to make certain that the subsoil is really moist before planting. Stake each plant and leave one main stem, removing all side shoots. Six or at the most seven fruit trusses can be safely allowed. Correct watering and ventilation are very important, for they affect considerably the plant’s resistance to disease. Watering should be done in sunny weather and can be less frequent if the ground is heavy — where the soil is very light a mulch of partially decayed manure, straw or peat is strongly recommended.

The art of good ventilation can only be learned by personal experience — more air should be given in damp, dull weather than when it is bright and sunny. Removal of the leaves as the fruit trusses develop is a very controversial question. Remember again that it is temperature rather than direct sunlight which ripens tomato fruit — defoliation done in order to give the plants more sun is therefore unnecessary, although it may be advisable to remove some leaves to allow free circulation of air.

Choice of Varieties:

Histon Early, Histon Ideal, Stonor’s Moneymaker, the Amateur, Best of All, Hundredfold, Market King, and Sutton’s Golden Queen are all reliable.

Tomato Diseases under Glass:

Damping Off. Damping off is a very common trouble among seedling plants generally, and is encouraged by warm, moist conditions. Infection takes place either in the root or at soil level and the plant turns brown, shrivels up and will probably collapse completely.

Cheshunt compound will prevent this disease if applied when pricking out, at transplanting, and at any time subsequently. Infected plants receive no benefit from the solution because the fungus is already inside the tissues where the liquid cannot reach it.

Foot Rot or Black Leg. This is a condition in which the roots or base of the stem turn quite black, so that the plant often falls over. The disease may occur either during the planting out stage or much later, and though tomatoes sometimes recover, such plants may wilt while the fruits are forming. Early sterilising of beds, pots or boxes, as for damping off, will control foot rot.

Green Back. This trouble (sometimes referred to as yellow back) often worries the amateur but is quite easily remedied. The symptoms are unmistakeable; the top of the fruit near the stalk remains hard and green, eventually turning yellow, while the rest of the tomato is changing to the normal red. Green back is partly due to shortage of potash, but the immediate cause is usually that the top of the fruit becomes too hot through strong sunlight.

If the plants are well supplied with potash before planting time and enough foliage is left to shade the fruit, this condition is much less likely to arise.

Greenhouse White Fly. This pest occurs quite frequently in greenhouses and is liable to attack any type of plant grown under glass. The minute white flies are not difficult to kill but are very active — the slightest movement of the foliage causes them to rise and fly to other plants. These insects can do considerable damage to tomatoes — in addition to spotting the leaves, they cover them with a sticky, sweet substance usually known as ‘honeydew’. Spraying and dusting are often ineffective owing to the waxy covering of the flies and their extraordinarily rapid movements. Fumigation is therefore the only effective means of control, using gamma-BHC (lindane) smoke generators.

Tomato Leaf Mould. Though this disease can kill an entire crop of tomatoes and is often very prevalent in commercial houses, it can be checked by very elementary precautions. Leaf mould of tomatoes is known by various names — tomato rust, blight or mildew — which are certainly descriptive if hardly accurate! It does not attack plants grown outdoors and would appear to be due to excessive humidity in conjunction with drought at the roots, brought about by incorrect ventilation. Over-feeding with strong nitrogenous fertilisers may predispose tomatoes to leaf mould. To control this disease make sure your plants are not over-crowded and that your greenhouse is adequately ventilated, not only at the top, but if possible, at the ends and sides of the building. Preventive spraying is also necessary as once established, the disease is not easy to eradicate. Salicyanilide and thiram fungicides are well-known control measures.

Picking and Storing of Tomatoes. Tomatoes should be picked with the calyx attached to the fruit. Grasp the tomato firmly and bend it towards the main stem which will then break at the joint just above the calyx. Always gather fully ripe tomatoes immediately, or the ripening of the remaining fruits will be delayed. Bird damage can be avoided by picking as the tomatoes start to turn red.

When ripening tomatoes on greenhouse shelves or window ledges, remember that they must not touch the glass, as this is liable to cause tomato scald. It is best to mix ripe and unripe fruits, for the ripe ones produce a small amount of gas which speeds up the ripening. All partially ripened or green fruit will develop quite satisfactorily indoors, if stored correctly. Tomatoes intended for storing must be gathered when quite dry — the calyx in particular must be absolutely free from any moisture. Be careful not to bruise the fruit when picking, or the keeping qualities will be affected. Never store tomatoes showing the least sign of decay.

Arrange the tomatoes in single layers in trays, making sure that they do not touch one another — the rows can be separated by strips of newspaper. Place these trays in a drawer, cupboard or other place where the temperature does not fall below 52 degrees F. (It should not drop below 50 degrees F. at night.) Lower temperatures can render the fruits definitely susceptible to disease.

Experiments some years ago at the John Innes Horticultural Institution produced results of real practical value to amateur gardeners. They may be summarised as follows.

Temperature and not light is the chief factor in ripening green tomatoes, a temperature of 52—54° F. being the most suitable. An increased temperature up to 70 degrees F. shortens the ripening period and restrains the development of any disease.

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