APPLES, pears, apricots, cherries, peaches, nectarines, plums, figs and grapes can be grown in any lean-to greenhouse or small conservatory facing the south and not shaded or darkened by trees or buildings. With no heat other than that of the sun first-class fruit can be produced, and crops will be earlier than those outdoors.
With artificial heat the fruits will be gathered still earlier, melons can be added to the foregoing list, and strawberries be picked in April.
How They are Grown.
Melons – which cannot get along without heat – are grown on mounds or a bed of soil made up on the heated greenhouse bench. Strawberries for forcing are fruited in pots six inches in diameter.
All the others listed in the opening paragraph can be grown and fruited in 12-in. diameter pots; grapes, figs, peaches, nectarines and apricots can also be planted in a properly prepared border and trained either to the back wall or to wires running parallel with and about 9 in. distant from the front and roof glass.
Fruit Trees in Pots.
Small trees grown on dwarfing stocks and trained as compact pyramids or bush trees can be purchased in suitable varieties and of fruiting size, in 12-in. diameter pots. In those same pots, given correct attention, they will thrive for years.
When their fruit has been gathered, in early summer, they are shifted from the greenhouse or conservatory to a sunny spot outdoors for the sun to ripen their new wood and get the fruit buds in condition for next year’s crop. There they remain – not neglected but tended according to their special requirements – until the following February, when they go under glass again. Exception is made in the case of indoor varieties of grape and figs in pots; these need the winter protection of the greenhouse or conservatory.
Keeping Pot Trees Fruitful.
Soil in a 12-in. flower pot is called on to do a lot. Some of it must therefore be renewed each autumn, when the leaves have fallen. To do that, the plant has first to be removed from the pot. There are two ways of doing this. The tree may be gripped by the stem with one hand and lifted (together with the pot, of course) 1 in. from the bench or the ground, the rim of the pot then being given a smart rap or two with the handle of a trowel held in the other hand. If the pot does not then come away the other method should be tried.
This requires an assistant. Tree and pot are inverted, and whilst the assistant steadies the tree the other operator raps the pot rim upwards – holding the pot with the other hand to avoid accident.
When the parting has been effected, the tree is placed on one side whilst the pot is scrubbed thoroughly inside and out and the crocks (bits of broken pot covering the drainage hole) are dealt with similarly. Whilst these are drying the soil mass can be dealt with.
New Soil for Old.
To allow of new soil being used some must be taken away from the mass surrounding the roots. The top inch or so can be removed first, with a piece of stick held as though it were a pencil. Then the soil surrounding the roots is loosened and allowed to fall away. Soil at the centre, around the larger roots, can remain.
The tree is then to be replaced in the washed and dried and re-crocked pot and the new soil filled in and made very firm. For this purpose the ideal soil mixture is old turfy loam (soil so filled with fibre it can be torn to pieces) three parts, and quite rotted stable manure one part; charcoal and a scattering of hydrated lime willimprove the mixture. If there is difficulty about contriving this mixture at home the small quantity needed should be purchased from a nurseryman.
The mixture of the items should be thorough, and the whole should be warmed through, by exposure (in the greenhouse) to sun for a few days. It should therefore be ready before repotting is actually due.
How to Repot. A handful of old stable manure or leaf-mould should be placed over the crocks above the drainage hole, then a handful of the soil mixture placed on top of that and firmed down with the fist or the blunt end of a rammer – a piece of broomstick about 1 ft. long, one end cut square, the other wedge-shape (,A) The tree, held by the stem, is then placed centrally in die pot and soil trickled in with the other hand, quite loosely, until the pot is half-full. Roots should then be arranged so that they are not bunched and more soil added – the pot being shaken vigorously on die bench to ensure that soil trickles into all crevices and that no small spaces between roots remain unfilled. The soil is then rammed, first down the sides of the pot with the wedge end of the rammer, the square end being used above the roots. More soil is added, and rammed, undl die surface stands finally within about 2 in. of the pot rim. The top ½ in. of surface soil should not be rammed but left loose.
That completes repotting, and the tree can be stood outdoors again until February. When that month arrives and the tree is due to go back into the greenhouse or conservatory the outside of the pot should be cleaned with a scrubbing brush, and the tree sprayed with winter wash to ensure that it goes in with a clean bill of health.
Preparing a Greenhouse Border.
If a grape vine, fig, peach, nectarine or apricot is to be planted permanently inside the greenhouse or conservatory die ground must be prepared with some care. The vine or tree will be expected to fruit heavily, without a break, for many years; which it will do if it is provided with adequate rooting conditions.
It is common practice to plant a grape vine outdoors at the foot of greenhouse or conservatory and lead the stem in through a hole low down. Provided the outdoor bed is well drained and the soil to the vine’s liking, the method will serve. But the vine in those circumstances is not under such complete control as when the roots themselves are within the greenhouse.
The grape vine with its roots out in the cold and wet and its head in the warmth of a greenhouse cannot be expected to put up the same sort of show as the vine which is all enclosed.
An inside border should be about 4 ft. from front to back. To make a really profitable job of it the border or bed should be dug out to the depth of about 3 ft., the top foot of soil being placed aside – it is the most fertile and therefore should be returned last of all. The bottom of the hole should be lined with stones and broken brick, this drainage material to be about 9 in. deep after being rammed.
The hole should then be filled in again, preferably with good fertile soil taken from the open garden; if tliis is light in nature chopped turves or substantial loam mixed with it will be an improvement. Should there be no other soil for refilling than that which was taken out, crushed mortar rubble, or hydrated lime, should be mixed with it, plus bone meal at the rate of a 6-in. potful per barrowload of soil; that which was the original top soil again being used as the top.
In any case the bone meal should be mixed in, and for stone fruits (peach, etc..) mortar rubble or hydrated lime is essential. As the soil goes back into the hole it should be trodden firmly, so that there shall be no sinking to cause trouble to the roots later on.
Replacing Surface Soil. The inside fruit border is kept in order by a renewal of the surface soil every winter. The old soil should be scraped off carefully, in November, with a stick and the fingers, to the depth at which the topmost roots are exposed, and taken outside for disposal elsewhere. Its place is taken by fresh soil – fibrous loam if possible – enriched with a sprinkling of bone meal or ½ in. bones, with the addition of mortar rubble or lime in the case of stone fruits.
Fertilizing Indoor Fniit Blossom.
The artificial conditions in which under-glass fruit trees are grown make it necessary that at blossoming time the flowers should be hand pollinated. The transference of pollen is effected by twanging the wires to which plants are trained; or by dabbing or brushing the open flowers gently with a tuft of dry, loose cottonwool tied to the end of a stick
A rabbit’s tail is sometimes used in the latter manner.
This should be done when the atmosphere is dry and the sun shining; pollen travels then most readily. If this is repeated on three or four successive days, a good set of fruit should be ensured.
Summer and Winter Pruning.
These and other attentions, and names of the most suitable varieties for fruiting in pots and in the indoor border, are detailed under names of fruits in die alphabetical section. Ventilation and general management of a greenhouse are explained in the section FRAME AND GREENHOUSE in the vegetable section.
The microscopic red spider, which sucks the sap from leaves, can be kept down by constant syringing with plain water; but this syringing must be temporarily discontinued when the trees are in flower, and again when fruit is approaching the ripening stage. A dry, close atmosphere encourages this pest, so whenever it is possible the air, the greenhouse bench, and path and walls, should be kept moist.
Green fly can be got rid of by fumigating the greenhouse or conservatory, as explained in the section PESTS AND DISEASES OF VEGETABLE CROPS.
Keep the Greenhouse Clean.
A fertile source of trouble in the greenhouse is miscellaneous rubbish allowed to accumulate on the floor beneath the staging. Wood lice and other pests lurk among the discarded flower pots, seed boxes and similar items, which have been carelessly cast aside there. It is for them a most convenient nursery wherein to raise their families.
They should be denied this facility. The greenhouse should be maintained in as cleanly a condition beneath the staging as elsewhere. A further precaution consists in scrutinizing most carefully every pot before it is introduced to the greenhouse. Any plant showing traces of pests or disease should be given the appropriate treatment before it comes under glass.
Sheltered from their natural enemies – birds, frogs, etc.by greenhouse conditions, pests have the chance of an easy life and rapid breeding. The vigilance and care of the grower must be directed to the complete cancelling out of anything which is in their favour.