Cultivation of Peaches and Nectarines
Peaches and nectarines are types of Prunus persica, the difference between them lying in the felt-like skin of the former and the smooth skin of the latter. Like the vine, the peach and the nectarine pose problems for cultivation in small. It is asking too much to expect a vigorous bush to perform well under severe restriction, and gardeners would be well advised to consider these problems before embarking too enthusiastically on their cultivation. An alternative may well be to grow them in pots.
Traditionally peaches are grown on the wall of a south-facing lean-to, a practice which fits in well withbeing grown against the glass. Alternatively the peaches can be grown against the glass 30-38cm (12-15in) from it and a vine run along the ridge from the end. To do real justice to a peach, a wall height of 3-3.5m (10-11ft) will be necessary, with commensurate height for the glass portion. They can be excellently grown in a span-roofed structure on an alternate staggered arrangement where more than one bush is grown, and a greenhouse with a width of 3-3.5m (10 — 12ft) and 2.5-2.75m (8-9ft) high will give reasonable room for development.
may be cold or heated. Adequate roof and side ventilation is important. Supporting wires should be run 23-25cm (9-10in) apart in vine eyes 810m (3-4in) from the wall or 23-25cm (9-10in) from the glass, or some other support provided.
Heat given early/mid-winter — fruit harvested early summer
No heat — fruit harvested mid—late summer/early autumn according to variety
Preparation for planting
The long-term nature of a peach or nectarine demands a thorough approach to border preparation. When theis initially of good quality and is in no way impeded, it will suffice to work through a reasonable quantity of broken rubble and well-rotted manure or compost to an area of 2 x m (6 x 3ft) per tree. Peat is now frequently used in quantity for and in this case lime should be applied at 120-150g (4-5oz) per bushel of peat to offset its acidity and in addition at approximately 1lb or more per sq yd of border, according to analysis, to bring the pH up to about 6.5, with a phosphate and potash index of between 2 and 3.
Where the soil is completely unsuitable, excavate to a depth of 60-75cm (2-2ft) for the area of 2 x 1m (6 x 3ft) referred to above. Fill up with a good layer of rubble through which is mixed any clean garden rubbish available, along with a liberal application of bonemeal and basic slag. Once again a good John Innes type compost (JIP2) will suffice, but the magnitude of the task shows the need to think in terms of improvement rather than substitution if at all possible. The roots of peaches and nectarines in modern greenhouses will invariably gain access to the outside soil and therefore it may be necessary to improve the outside area concerned.
A heavy mulch of well rotted farmyard manure should be spread over the surface sufficiently long before planting to allow a degree of drying out yet keep the mixture moist.
On delivery from the nursery, the tree should have its roots spread out in a wide shallow hole, after removing any roots damaged in transit. Deep planting is not advisable, 5-8cm (2-3in) of soil over the top roots being all that is required. Leave a space of 10-13cm (4-5in) against the wall or the side of the greenhouse. Water in thoroughly. Tie branches loosely to support wires or trellis framework; these are finally spaced out and secured afterand before growth starts in the spring. If trees are bought with a well-developed fan shape, the main branches should in the first pruning be cut back to about half their length to encourage the development of new side shoots, as peaches and nectarines fruit on the previous year’s new wood and a constant supply of this is necessary to keep the tree productive. The training of a young plant requires more detailed information than can be given here.
It is important that from the time growth commences there should be a plentiful supply of moisture, otherwise a newly planted tree will draw on reserves of sap and possibly collapse and die back completely.
Flowering, pollination and setting fruit
Blooms will be produced very early in the season, being formed while there is very little leaf growth. Pollination must be assisted by tapping the branches and dusting the open blooms with a rabbit’s tail or cotton wool on a cane, keeping the air dry and the house relatively cool at 7.2-10°C (45-50°F) — if this is not made impossible by other activities. If it is, then the peach or nectarine must take ‘pot luck’ and there may be very erratic setting and fruit production.
Much can be done to encourage growth and good setting by syringing or hosing with a fine rose early in the morning of a day which promises to be bright, this being a practice which should be persevered with until fruit is well formed. Dryness of atmosphere will also induce red spider attack.
After it is seen that tiny fruits have set, the temperature may be gradually increased to 18.3-21.1°C (65-70°F) by day and 12.8-15.6°C (55-60°F) by night, emulating the conditions experienced in out-of-doors culture later in the season. Vents should be shut down early at night to conserve heat as much as possible.
Thinning of fruit
Thinning to avoid over-cropping is generally done first to a limited extent after the tiny fruits are set, then later to about one fruit per 30cm2 (square foot), or roughly one fruit per shoot, this taking place over a period when the fruits are the size of small walnuts 1.25-2cm. Remove with scissors to avoid tearing the bark. During this second thinning period high or erratic temperatures must be avoided, or a large fall of fruit may be induced.
Surplus growth must be rubbed out (gradually, to avoid shock) throughout the season when 2.5 centimetres or an inch or so long, except during the flowering period, the object being to rub out all buds growing outward, leaving only two or three well placed to replace the shoots presently bearing fruit. Failure to remove surplus shoots and loosely tie in the remaining young growth will result in a forest of growth and a completely unmanageable tree.
As the fruit ripens it should be allowed the full benefit of the sun by tying’ aside any growths that shade it. When picking the fruit handle it very carefully, especially peaches which bruise very easily.
After the fruit is gathered, frequent hosing of the foliage should be carried out and full ventilation given, along with plenty of water at the roots to coincide with the mild autumn rains they would receive out of doors. The application of very diluted liquid manure is also advisable to strengthen the shoots and buds for next year.
When leaf fall is complete the tree should be carefully pruned, cutting out suitable old shoots which have borne fruit and tying in well-placed new shoots. There must obviously be compromise here, e.g. a fair proportion of old shoots must be left because of new shoots coming from them. As the tree grows pruning becomes more exacting, and gardeners are again reminded that they should not enter into the growing of peaches or nectarines unless they arc prepared to give the detailed attention necessary.
Where trees are over-vigorous and nonproductive it may be necessary to carry out root pruning by completely lifting trees up to 5 or 6 years old, cutting off strong tap and coarse lateral roots and replanting. This is carried out in the dormant period.
Each mid to late winter give a top dressing per tree of 200-226g (7-8oz) of a good compound trace-element-containing fertilizer, scattered evenly over the ground for a reasonable area out from the tree. Each autumn after the fruit is gathered apply 270-400g/m2 of hydrated or 540g/m2 (1lb per sq yd) of ground limestone. Over-vigorous trees should not be too liberally fed. Weak trees can be fed more generously to the extent of applying stimulants during the growing season or giving additional nitrogen as in sulphate of ammonia in late winter at 34-65g/m2 (1-2oz per sq yd).
White fleshed and yellow fleshed peaches and nectarines are available, fruiting according to level of heat and variety from early summer to the end of early autumn.