This section is from the book "The Gardener V2", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Give the earliest trees a good washing with the engine as soon as the fruit are all gathered, and continue to do this frequently to keep them clean and healthy. If there be any spider about them, put a handful of sulphur in the water. Look to the inside border, and if it is dry give it a good watering with manure-water. Look over the trees, and remove any superfluous shoots, so that sun and air may circulate about every leaf and shoot. Air freely all fruit now ripe and ripening, and look over them daily and gather those that are ripe. If to be packed and sent to a distance, gather before they are quite ripe. Trees swelling off their crops in various stages should be well syringed at shutting-up time. Very little fire-heat is needed now; but if the weather be dull and damp, keep a little heat in the pipes, or mildew may put in an appearance. Thin the fruit in late houses, and all shoots not needed to furnish sufficient for next year's crop should be removed at once. Pay particular attention to the state of the borders, and never let them get dry. All borders should be mulched with manure.
Pinch and regulate the growths of young trees inclined to grow unequally.
Give ripening fruit abundance of air night and day. Water the borders of those swelling off crops, and if they are old trees in full crop, give liberal supplies of manure-water. Syringe freely and frequently all trees, except, of course, those on which the fruit is ripe and ripening. But as soon as the fruit is all gathered resume the use of the syringe, so as to keep the foliage clean and healthy. If red-spider has put in an appearance, mix a handful of sulphur with the water every time they are syringed. Keep the house cool and well aired, and examine each tree, and if there are more shoots than are necessary for next year's crop, cut them out at once, so that light and air may play freely about every part. Attend to the tying of the growths of young growing trees - tying them in their proper place - and avoid crowding. See that no tree in any stage is allowed to suffer for want of water.
Look carefully over all trees from which the crop has been gathered; and if there are more shoots than are necessary for properly furnishing the trees for another year's crop, remove them, so that all the air and light possible may get at every leaf and shoot. See that these do not suffer from dryness at the root if the weather be droughty; and if the foliage is infested with red-spider, syringe or engine them freely - putting a handful of sulphur in the water - till the enemy disappears. It is of the utmost importance that the foliage be kept healthy to the last, or the buds will not be matured as they should be. Let sun and air play freely about ripening crops. If any of the fruits be shaded with leaves, fix them aside. Examine the fruits every day, and gather them before they drop. Fruit to be sent direct to table for dessert, should not be gathered until a very gentle pressure removes it from the tree; but when to be sent to a distance - especially if to market - they should be gathered earlier, or the chances are that they do not travel well.
Late crops in cool houses should have liberal waterings, until they begin to ripen.
Trees from which the crop has just been gathered, if growing strongly, should have a circulation of warm air about them; and should the weather prove sunless, let artificial heat be applied to this end. If there be any signs of red-spider about them, give them a few vigorous washings with water, in which a handful of flower of sulphur is mixed. Remove any superfluous shoots that may have been tied in, so that air and light can act on all parts of the trees. Late crops in cool houses will now be ripening, and will require to be examined every day, and all ripe fruit carefully gathered. If this be neglected, the fruit are apt to fall off and get bruised.
Protect them from flies and wasps; and any leaves that may be shading the fruit should be pushed aside, so that it may be properly coloured by exposure to light. See that the borders do not become over-dry if they are inside.
If new borders and fresh plantations of trees be intended, get everything in readiness for planting, as soon as the trees have shed their leaves. To produce fine Peach-trees and fruit, the soil should be a rather strong loam, 2 feet in depth and thoroughly drained, and having no manure added to it except some bones. Apply fire-heat to all Peach-trees that are not likely to ripen well before they shed their leaves, and syringe the leaves occasionally on fine days to prevent the spread of red-spider, which thrives so well on fire-heat. On the other hand, let earlier and well-ripened trees be kept cool and well aired. See that borders inside do not get dry. Any fruit yet to gather should be well exposed to light and air.
All trees intended to be started next month should be pruned and tied at once. After they are pruned, and the wood and glass all cleansed, syringe the trees with paraffin and water, at the rate of a wine-glassful of the former to a gallon of the latter, and in five minutes after syringe with clean water. We find this the most thorough preventive of green-fly in the early stages of growth. Remove all the surface-soil from the borders, and treat as directed for Vine-borders, and water the inside border if at all dry. The leaves will now be off all the mid-season trees, and as soon as convenient prune and otherwise put these in starting order. The late trees will now be nearly leafless, and if the leaves are not adhering firmly to the trees they may be brushed off. See that no part of inside borders are allowed to get dry. Let all young trees be planted without delay.
Trees from which ripe Peaches are expected by the first week of May should be shut up at once, and kept from falling below 45° at night. By the middle of the month apply fire-heat sufficient to keep the heat at 50° when cold, and 55° when mild. Syringe the trees two or three times daily, after firing commences, with tepid water. See that the border is thoroughly moist, and any portion of it that is outside well protected with fern or dry litter. Prune and tie succession trees, and after they are tied, syringe them with paraffin at the rate of a wine-glassful to a gallon of water. This is the only dressing we use for Peach-trees now, and find it most effectual against green-fly, etc. Where young trees are to be planted, get the work completed as soon as possible. A heavy loam, thoroughly drained, and devoid of all animal manure, is best for Peaches. Do not cut the trees any further back than to hard well-ripened wood.