One of the greatest of favourites for eating and cooking, the tomato is of special value on account of its health-giving vitamins. Splendid crops can be grown in the open as well as in an unheatcd or heated greenhouse, either from purchased or home-raised plants. Moderately good soil, warmth, and a moist root-run are the chief requirements.
Early ripening varieties are necessary for outdoor culture; they include the following, which are also suitable for the greenhouse: Earliest of All, Princess of Wales, Abundance, Up to Date, Ailsa Craig, and, if yellow fruits are favoured, Golden Queen, Golden Nugget. If masses of large corrugated fruit are wanted, an excellent early outdoor variety is Open Air. Earliness in ripening is especially desirable when tomatoes are grown outdoors, owing to the comparative shortness of the summer.
The easiest method is to purchase young plants in late May (June in cold districts) for setting out 18 in. apart. A heated greenhouse or hotbed frame is needed for raising plants from seed. A small packet will suffice, 1 ounce of seed representing 2,000 plants. Seedlings appear in about ten days.
Ready for Use.
Outdoors, tomatoes are ready for picking at the end of July and up to late September; in an unheated, sunny greenhouse in early July and up to late October; in a heated greenhouse winter and early spring crops are possible.
For early and prolonged fruiting the ideal outdoor position is in full sun, shielded from cold winds, as at the foot of a fence or wall facing south or west. If that is not available plants may be set out in rows in the open, these to run north and south, thus securing an equal share of sun on both sides of each row.
These should be about 9 in. high, close jointed, thick stemmed, dark green with a bluish tinge, and preferably showing the first flower truss. Avoid leggy plants with light green foliage; they have been rushed in considerable heat and not properly hardened off for planting out. If small white flies are present the plants will be dear at any price.
They should not be purchased before late May for outdoor planting. Those raised in pots give the best crops; plants from boxes have been cramped for root space and are not so suitable.
The site should be dug 18 in. deep, with leaf-mould or hop manure worked in 9 in. down, and plenty of wood ash (from the rubbish fire) mixed with the top soil. Stable manure may be used, but unless it is quite old it should not be nearer the surface than about 9 in. Manure near the top at planting time results in gross, unfruitful growth. If nothing of this nature is at hand for enriching the ground, dig in well decayed material from the soft refuse collection.
When and How to Plant.
The end of May is early enough to set out the plants; if the weather is specially favourable they might beplanted as early as the middle of the month, but the possibility of destruction by late frosts must always be taken into account. In colder midland and northern districts the wise rule is to play for safety and defer planting a few days into June.
If the soil in the pots or boxes containing the plants is other than moist, soak it right through an hour or two before planting. Remove them from a box with a trowel; from pots in such a way that the ball of soil surrounding the roots is not broken, and remove the drainage crocks.
Planting holes, made with the trowel, should be more than large enough to take the ball of soil and roots. When the plant is in position well-crumbled soil is worked down the sides of the hole, until this is filled, and firmed with the butt end of the trowel. The plant should rest at such a depth that the top of the ball of soil is just covered.
The surface of the filled hole should be 2 in. lower than the surrounding level, to hold water when this is given. If this depression is about 1 ft. across, so much the better.
Roots should be about 6 in. away from the base of fence or wall; in this position the depression would be semicircular and not round in shape. Plants to be 18 in. apart. If grown in rows the latter should be 3 ft. apart.
They should be started off with a good watering; and if the weather is very bright and the leaves show signs of drooping the plants should be shaded with paper whilst the sun is on them, at any rate for the first couple of days.
For a week or so after planting tomato plants should have nightly protection, in the form of paper hoods, or inverted boxes can be placed over them, as a safeguard against frost, the covering to be removed by day.
Staking and Tying.
Stakes are essential, whether the plants are against fence or wall or in an open bed, and should be put in place as soon as night protection ceases to be necessary. They need to be really strong, should be pushed deeply into the ground about 3 in. behind the plant, and should stand about 5 ft. above the surface.
Tie each plant to its stake with raffia or thick string, the loop to be loose enough to allow room for stem expansion, more ties to be given as the plant extends its growth upwards.
Keep to Single Stems. It is the nature of a tomato plant to produce several stems, diese beginning as small side shoots arising in the angles between leaves and main stem. All these should be removed as soon as they appear, leaving only the single main stem; the object being to divert all the energies of the plant to a few large trusses of fruit.
A watch needs to be kept for these side shoots; they are produced lavishly, they lengthen very speedily, and some are apt to be overlooked among the general foliage. They can be broken out from their sockets with a push of the finger, or be nicked out with the point of a pocket-knife blade.
Watering and Feeding.
Tomatoes are thirsty plants and in dry weather water ought not to be stinted. They are hungry, too, but feeding from the surface should not begin until the first fruits on a plant are rather larger than marbles. One of the special tomato fertilizers can be used (sold by seedsmen and some chemists and at the big stores). A spoonful per plant once a week is sufficient, sprinkled on the soil above the roots and watered in.
If roots appear at the surface, cover with 1 in. of good soil with which a little of the special fertilizer has been mixed. Make this top dressing firm.
When to Remove Tips.
In a hot summer, plants set out early can ripen five trusses (bunches) of fruit, but four is the normal number; in cold and late districts three trusses is the limit of a plant’s ripening capability. According to the local conditions, each plant should be stopped when its third, fourth or fifth truss has developed.
Stopping alludes to further upward growth, which is prevented by cutting off the extreme tip of the plant’s main (and only) stem.
This is done because the plant is carrying all the fruit that is likely to ripen outdoors, and the production of more trusses is not required – they would come to nothing.
Other shoots appear later at the point where the tip was removed, and these should be treated like the lower side shoots – promptly dismissed.
Why Tomatoes Split.
Cracks in the fruit result from drought followed by heavy rain or generous watering. The trouble is avoided by seeing that the soil never becomes actually dry; when it approaches that condition a bucket of water per plant is not too much.
Fruit should be gathered not by the complete truss but individually as they ripen. They are ripe when fully coloured all over. Break off each fruit, complete with a short piece of its stem, as soon as it is fit for taking. Gentle handling is necessary. The skin easily bruises.
Odd fruit here and there sometimes seem reluctant to colour all over; they are marred by yellow patches. Generally this is due to lack of sufficient potash in the soil. The cheapest source of potash is wood ash, and this should be worked plentifully into the top soil before planting. A spadeful per plant, followed by a good watering (without the wood ash being washed away), when the first trusses have formed will do a lot to prevent this yellowing.
Late in the season, when it is obvious that remaining tomatoes will not ripen in the open, trusses or individual fruits should be cut off; the trusses to be hung up inside the sunny window of a warm room, odd fruit to be placed in similar surroundings, to complete the ripening. A warm pantry or cupboard will do as well. The amount of light seems to have little to do with this artificial indoor ripening; it is temperature that counts.
There is a point beyond which unripe tomatoes sometimes refuse to go. Those that remain more or less completely green are still of considerable use, in the making of pickle or chutney for out-of-season use.
Tomatoes in Store.
Ripe (but not over-ripe), unbruised, healthy fruits will keep satisfactorily on a shelf indoors, if picked dry or wiped dry with a clean cloth. They should be placed in a single layer and without touching, where there is a current of air, no dampness, and where the temperature neither rises nor falls unduly. A sheet of paper placed above them will protect them from dust. They must be looked over occasionally and thoseshowing a wrinkling of the skin used up first. Any showing sign of decay should be ejected immediately.
Raising Plants from Seed.
There is nothing specially difficult about this, apart from the chief requirement of a steady temperature of about 55 degrees (by night) combined with full light. The seeds germinate better in darkness than in full light, but the latter is absolutely essential from the seedling stage onwards – which rules out a warm room cupboard as a makeshift greenhouse.
Tomato seedlings will come up quite satisfactorily in a warm living-room; the snag comes when the potted-on seedlings, still requiring those 55 degrees of warmth, cannot be given the maximum light.
To raise plants for fruiting outdoors or in an unheated greenhouse seed is sown in February or March, in a greenhouse or hotbed with a nignt temperature of 55 degrees; very thinly in small pots or a shallow seed box filled to within ½ in. of the top with a mixture of good soil two parts and one part finely sifted leaf-mould. The seed is covered A- in. deep, and the pots or box covered with glass and then paper – to keep moisture in and light out. This covering is removed directly seedlings are visible.
Transfer to Small Pots.
To bring seedlings to the stage when they need shifting separately to small pots great care is necessary in watering. Water, of the same temperature as the hotbed frame or heated greenhouse, is to be given only when the soil is approaching dryness; otherwise many of the seedlings will damp off – flop over at the base – and that will be the end of them.
When they are between 1 in. and 2 in. high they are due for transference singly to 3-in. pots filled with the soil mixture as advised for sowing. They are fragile at this stage and need very careful handling; bruising has to be avoided when pressing the soil down around the single stems.
Watered in, they are then stood close to the glass to be kept short and sturdy. If these pots become filled with roots by late April the plants will need to be shifted to larger pots, of 4-in. or 6-in. top diameter.
If pots are not available, seedlings can be shifted direct to shallow wooden boxes in which they are to stand 3 in. apart. But these never make such robust, fruitful plants as those given the more generous accommodation of flower pots.
Those intended for growing on in an unhcated greenhouse must be gradually accustomed to the lower temperature; those for planting outdoors must spend ten days or so in a sunny frame, with increasing exposure to outdoor conditions – which is known as hardening off.
Plants to be grown on and fruited in an unheatcd, sunny greenhouse are dealt with in much the same manner as those in a heated house, plants for the latter being raised earlier, of course. Planting can be done in the unheated house in late April.
Pots in which the plants are to finish, one plant per pot, should be not less than 12 in. across the top ; or boxes about 10 in. square and 1 ft. deep will be found quite suitable. Larger boxes can be used, and two or more plants be together; but there must be no crowding, or health will inevitably suffer. Each plant demands at least 12 in. of elbow room.
The pots or boxes are to stand on the greenhouse bench, as close to the front glass as possible. The crocks in the bottom of each pot, and the drainage holes in the bottom of each box, should be covered with a layer of leaf-mould or quite old manure, or hop manure. Roots will appreciate this when they get down to it. They are to be two-thirds filled with as good a soil mixture as can be contrived.
The ideal is fibrous loam – the top soil of a meadow after the good turf has been removed – pulled to pieces lumpily by hand, three parts, and one part leaf-mould; the next choice is fertile garden soil and leaf-mould mixed, with some fine sand or sharp grit added if it is on the heavy soil. During the mixing a good scattering of wood ash should be worked in.
Warm the Soil First. Plants will be checked in their growth if potted or boxed with cold soil. This should be warmed first, with die aid of a hot brick, a tray over the kitchen fire, or the oven; or exposure of small heaps to the temperature of the heated greenhouse for a few days will achieve this object.
Supports in the Greenhouse.
Each plant needs a stake long enough to carry it to within 9 in. of the sloping roof glass; to which it will then be trained parallel (on string or wire), at that same distance, if there is not sufficient space between pot and roof glass for the plant to be trained upright for its full length.
The plants are to be kept single stemmed, and tied, as explained for outdoor plants.
Watering under Glass.
Until the plants get hold of the soil in the final pots or boxes there will be no great call on the watering can. Whenever water is given it should be sufficient to soak right through the soil and drip out of the drainage holes. Then no more should be given until the soil is nearly dry again. Water should not be slopped around the floor or bench when tomato plants are in flower or fruit; they like the atmosphere to be drier then.
If water is given on sunny days, during the forenoon, the air has a chance to dry before evening; though in the height of summer the plants in pots, in full bearing, may need watering twice in the day.
Ventilation Needs Care.
On hot summer days, with no wind blowing, it may be necessary to open wide the door and ventilators of the greenhouse; at other times the giving of air demands caution. Tomatoes hate the air to be still and muggy; they also hate cold draughts. The ventilators will have to be managed with discretion.
Cold nights in late spring are a special peril where the unheated greenhouse is concerned. Tomato plants a few inches from the glass are within the influence of outside cold, and will need additional protection in the event of frost. This can be given in the form of sheets of paper placed between the plants and the glass.
Setting the Fruit.
Tomato flowers need to be fertilized to ensure the production of fruit. The fertilizing pollen can be distributed by tapping the stakes (or other supports) to which the plants are tied; a sharp tap or a jerk is sufficient, once or twice a day whilst they remain in flower. But it is no use doing this when the atmosphere of the greenhouse is damp; it should be dry, and the sun shining.
Feeding Greenhouse Tomato Plants.
The space that was left at the top of each box or pot (they were only two-thirds filled) when the plants were given their final shift should be filled in, to within 1 in. of the top, when the plants come into bearing. The same soil mixture should be used, enriched with a handful of wood ash per plant or a teaspoonful of one of the special tomato fertilizers. The latter should also be given once a week from then on, watered into the surface.
If any leaves in positions low down on the stems wither they should be removed. Foliage that shades trusses from the sun or is very crowded can also be shortened back to let in light and air; otherwise, healthy foliage (apart from the unwanted side shoots, to be removed as explained in the case of outdoor crops) should be interfered with as little as possible.
White Fly and Other Troubles.
White fly attacking greenhouse tomato plants must be got rid of by fumigating with one of the special preparations sold for dealing with this particular pest.
The presence of root knot disease is indicated by the foliage drooping and yellowing; the stem then becomes limp, and the plant collapses. Minute eelworms in the roots are the cause. Sleepy disease causes leaves to droop, and later on mildew appears on the lower parts of stems. Canker of the stem starts as gummy, moist patches, which become hard and dark and then whitish. Black stripe attacks the stem low down and works upward. In each of these cases affected plants should be uprooted and burned, and the soil should be treated with quicklime before it is used again.
Various forms of leaf-rust are – sometimes troublesome, the leaf, in some instances, rolling up and dying. In early stages the disease may be prevented from spreading to healthy leaves by dusting these with flowers of sulphur, affected leaves being picked off and burned. Fruit itself is sometimes attacked by black spot disease; those so disfigured should be removed and burned.
Generally these troubles may be avoided by starting with clean, healthy plants, keeping the atmosphere of the greenhouse reasonably dry and giving plenty of air, ample space between plants, and all the light possible.
The disease that is most troublesome to outdoor tomato plants is that known as blight; it is the same as that which attacks potatoes. It appears in the form of brown blotches on the upper surface of leaves. It can be controlled by spraying with Bordeaux mixture, but this must not be used when the fruit is ripening. The mixture can be purchased, with directions for use. One other disease – septoria – is dealt with in the chart’ Remedies Against Enemies of Vegetable Crops ‘.
Preparing for Table.
Fruit should be cleaned by wiping with a damp cloth, and then, if for serving raw and whole, polished with a dry cloth. The tomato is particularly valuable as a source of vitamins A, B and C. As regards A and B, it is equivalent to lettuce and green beans; in regard to vitamin C it is equivalent to such fruits as oranges and lemons.