Peach Trees: Feeding, Watering and Pollination
Because peach trees need to make a lot of vegetative growth to crop well, they need plenty of nitrogen. Generous feeding is necessary; over-generous feeding, however, will lead to lush, sappy growth and reduced crop yields. For a tree growing under normal conditions in moderately good, top-dress each spring with a balanced compound fertilizer, at the rate of 90 g per sq m (3 oz per sq yd). At the same time give a light mulch of rotted manure or garden . Once the fruit have started to swell, give a proprietary liquid feed every seven to ten days; stop the proprietary feed when the fruit begins to colour.
The soil at the base of a wall can become very dry, particularly in early to mid-summer. Prolonged lack of water may cause poor fruit set and excessive fruitlet drop, so water the soil thoroughly during dry weather. This is particularly important at blossom time and when the stone is developing. Lastly, avoid growing anything in the soil under the peach tree which would compete with the tree for moisture or nutrients.
Most peaches are self-fertile, but crops are more assured if you hand pollinate. Gently brush the flowers when fully opened with a rabbit’s tail or soft camel hair brush tied on the end of a bamboo cane, to assist pollination. Misting the flowers with lukewarm water on sunny days also improves the chances of successful pollination.
Because peaches flower early in the season, some protection against frost may be necessary. If frost threatens while the flower buds are opening, cover the tree with garden netting or cheesecloth. Be sure to remove the cover whenever the temperature rises above freezing, or the trees will not receive the fullest exposure to sunlight and insects will not be able to visit the flowers.
Growing Peaches under glass
In cool climates, fan-trained peaches are consistently better croppers when cultivated under glass. Protection from frost, sudden weather changes, manyare the benefits of greenhouse growing. Against this must be put the fact that more time must be devoted to cultivating peaches under glass, and their requirements are such that it is unlikely that the greenhouse can be used for growing other fruits or vegetables at the same time.
Vigorous control of the tree size is necessary for peaches grown in a greenhouse. A fairly common mistake is to plant two peach trees in a greenhouse where there is only space for one fully grown peach tree; eventually both trees will need severe pruning and their productivity will then be diminished. Although a newly planted peach tree may look somewhat small relative to the size of the greenhouse, remember that it will ultimately need about 3.7 m (12’) of wall space.
The greenhouse need not be heated; if heat is available, the season can be extended by forcing early crops, and by growing late varieties, which would not normally ripen fully outdoors. Heated or unheated, to comfortably accommodate a single peach tree the greenhouse should be at least 3.7 m (12’) long and 2.2 m (7-1/2) to the ridge. A lean-to should be the same length and ideally slightly higher at 2.5 m (8-1/2′) with a wall facing the mid-day sun. The fan is trained to follow the sloping roof line in a span house. A series of parallel, horizontal wires are fixed against the wall and roof, about 37 cm (15”) away from the glass. The first wire is 45 cm (18”) off the ground, and the rest are spaced 20 cm (8”) apart. In a lean-to, the fan is grown against the back wall. Here, the only heat will be that of the sun, and the advantages of growing peaches in an enclosed greenhouse will be slightly lessened.
The soil in the greenhouse border should be well prepared before planting; prepare as for growing a tree outdoors against a wall. If it is a small greenhouse, the roots can be allowed to grow under the walls and into the soil adjacent to the greenhouse. Remember, though, that in time the roots will become very thick and large, and may damage the foundations of the greenhouse. If the roots are to be contained within the greenhouse border, it is doubly important that there is sufficient depth and area for the roots to grow, and enough slow acting nutrients to support growth and fruiting. Pay particular attention to drainage, as soil in a confined border can quickly go ‘sour’ if waterlogged, killing the tree roots in the process. If the soil is at all heavy, it is a good idea to improve drainage by raising the soil in the border, with an open-jointed brick retaining wall. There should be 90 cm (3’) of soil depth, in total, so the brick retaining wall can be from 15-75 cm (6-30”) high, depending on the amount of extra drainage needed. Excess water will drain through the open vertical joints in the wall, indicating when the soil is saturated.
Take care over watering, feeding, po1-1ination and ventilation. The amounts of water given will vary according to the season, and the stage of development of the particular tree. As a general guideline, 10 L of water per sq m (2 gal per sq yd) should be enough for two months in the winter; the same amount will last about three weeks in spring, and two weeks in summer. Remember that this is only a general guideline; if the summer is very hot and the leaves begin to wilt, apply water more frequently; if it is a particularly cold or late season, apply less. Whenever you do water, water thoroughly; never just dampen the surface of the soil. Syringe the trees when the flower buds begin to swell, and again when the flowers fade. Continue syringing until the fruit begins to ripen and then stop. Once the fruit has been harvested, syringe again until leaf-fall in autumn. Syringing also keeps down the risk of red spider mite infestation. In very warm weather, damp down the entire greenhouse, to create a moist atmosphere.
Although bees and other insects may enter the greenhouse through open vents and some self-pollination may occur, it is best to hand-pollinate the flowers. Atmosphere in the greenhouse should never be close or stagnant, so the ventilators should be open whenever possible. This is particularly important from late summer onwards, as maximum light and ventilation allows the new wood to ripen.
After cropping, the fan should be untied from the training wires, and subsequently retied, with the lower shoots at least 7.5 cm (3”) apart at their tips. In winter, the glass should be cleaned, both inside and out, and the wall whitewashed. Scrub down all woodwork, and apply a tar-oil wash to kill any aphids or scale insects. Take away the top 2.5 cm (1”) of border soil, and replace it with a fresh dressing of loam, to which bonemeal and sulphate of potash is added.