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.
In this structure the success or non-success of the season may depend on one item of management - viz., watering, - that is, if the trees are restricted at the roots by pots or otherwise. Where there is a mass of fibre with plenty of drainage, it is difficult to over-water; but not only the pots or the immediate locality of the roots should be watered, but the whole mass of soil should be soaked, and a colouring of manure-water at each watering to the roots is better for the trees and fruit than stronger doses at longer intervals. The usual stopping and thinning of shoots will be necessary; syringing to keep off insects, and at no time should the trees be allowed to suffer a check of any kind. Shutting a house close at night, then throwing the whole wide open at once of a morning, is a mischievous practice : a little air should be on at night, and as the season becomes mild the whole air may be left on. Clean open surfaces, neatly mulched, is very desirable. Dustings of soot through the house are helpful to the foliage.
In this structure large supplies of water will be required, and to trees heavily cropped a colouring of guano in the water will be of much service. When fruit is ripening, water must be given moderately and free from stimulants. None should be allowed to become sodden. Syringe freely to wash off insects; mulch liberally, give plenty of air, and keep all surfaces sweet and clean. Expose fruits in all stages, especially when ripening, to sun and air.
In this structure trees will be at rest. If they are in pots they can be packed closely at one end, and the space used for protection for vegetables, such as Endive, Broccoli, Parsley, for use during severe weather, etc. If such space is not required the trees may be trimmed, cutting out all useless wood and any dead spurs. Put drainage right, and paint the trees with soft-soap and sulphur mixed, or Gishurst's Compound. If scale has appeared, a thorough washing of the parts may be necessary : surfacing of the pots may be left later, as the trees would not get the benefit of it in their present condition. Any transplanting or root-lifting of trees planted out not yet attended to, may be done as early as possible. Walls may be whitewashed; painting can be done when weather is dry. We prefer doing the inside of such houses when foliage is gone, and the outside in spring, except where lights can be taken off altogether. In such cases the trees in pots can be taken outside and plunged in ashes.