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.
Plants that were shifted four or five weeks since into their fruiting-pots, will, if treated as directed last month, have began to lay hold of the fresh soil, and to show signs of growing freely. Care must be taken to prevent a too rapid pace of growth for the present, while a good deal of fire-heat is necessary to keep up the temperature. The bottom-heat should not be allowed to range higher than from 85° to 90°, the former being quite high enough for young growing stock. When the days are light, avoid having much heat in the pipes, and shut up sufficiently early in the afternoon to run the heat up to 85° for a short time - at the same time dewing the plants slightly overhead, and damping vacant surfaces and walls, so as to have a moist atmosphere while the heat is high. Do not let the night temperature exceed 65° as long as the nights are cold, calling for considerable firing. High night-temperatures tell injuriously on Pines very quickly, and should always be avoided. Let the ventilation be regulated according to the state of the weather, and let it be attended to in the morning as soon as the heat gets to about 57°, increasing the amount of air gradually till 2 o'clock, when it should be gradually reduced.
See that the soil is kept just damp enough to promote healthy fresh growth, avoiding; dryness and overmuch watering. The early started Queens will now be swelling their fruit rapidly, and must have every encouragement. Keep them steadily moist by waterings of manure made from guano and sheep-droppings. Shut them up early so as to have a high temperature from sun - heat in the evening, allowing it to drop to 70° by 10 p.m. Let the air be kept moist in proportion to the heat. Syringe the surface of the bed, and give the plants a dewing overhead : avoiding wetting the crowns much, or they will grow more than is sightly. The bottom-heat for these should be kept as steadily as possible about 90°. Until fruit that are about fully swollen begin to colour, treat them as directed for the early Queens; but when colouring commences, give them more air and less moisture to develop flavour. Smooth Cayennes and Charlotte Rothschilds that are wanted to start six weeks or two months hence, should be kept cooler and rather drier for the next month; but do not carry this treatment so far as to cripple or stunt the plants. A time of comparative rest makes it the more likely that they will fruit when required. Any portion of the stock that are well rooted in small pots should be shifted at once.
If shaken out or much disturbed at the root, more shade will be desirable than earlier in the season, until they take with the shift.
Owing to the wintry weather which has prevailed all through March, till nearly the middle of April, early started Queens have not made such rapid progress as usual; and in cases where they are required as early as possible for the London season, they may now be pushed on with higher temperature. Let the night temperature not be lower than from 70° to 75° after 10 p.m. Shut them up early on sunny afternoons, so that the thermometer runs up to 95° for a time. Give a corresponding amount of air moisture by syringing the surface of the bed, and the plants themselves lightly. Keep the bottom-heat as steadily as possible about 90°; and see that the soil is never allowed to become really dry, but avoid keeping it very wet. Succession plants, shifted two or three months ago, will now be growing freely, and will require careful management as regards air-giving and watering. As soon as the thermometer touches 75° put a little air on, and increase it gradually till noon, when in calm warm days the ventilation should be liberal to keep the plants from drawing : 65° on cold nights, and 70° when mild, will be high enough all through this month.
Sprinkle the plants lightly every fine day when the pits are shut up, and moisten the surface of the bed and paths, so as to keep the air moist for the night. Keep the fires low by day when there is sunshine; for hot pipes, a brilliant sun, and maximum ventilation, make the atmosphere of the pits very injurious to young growing Pines. By raising the temperature, and giving more water at the end of the month, plants that have been resting for the last month or so can be started into fruit for the supply of ripe fruit in autumn. Keep those intended for starting in July steadily growing all through this month. In watering Pines in all stages of growth just keep the soil moist, avoiding anything approaching to a wet sodden condition. Heavy syringings over the plants is a practice we object to. The foliage should be dewed over through a fine syringe, and the moisture applied chiefly to the surface of the bed and paths, etc.
 
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