This section is from the book "The Gardener V1", 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 all vineries where the Grapes are not yet colouring, keep up a good supply of moisture in bright weather by frequent sprinklings of the paths and borders. Shut up as soon in the afternoon as the danger from an overheat is past, giving a corresponding amount of moisture while the heat is high, but putting on a little air for the night at 8 p. m. This treatment is only advisable when the weather is clear and bright, and a maximum of air-giving is necessary by day. On the other hand, when dull, sunless weather prevails, be content with less moisture, as with less heat it is an evil. The temperature should not be allowed to sink below 75° at night now, and for this end fires may yet be necessary in colder weather in some localities. See that all Grapes swelling off that have their roots in inside or elevated borders are not allowed to suffer for want of water in seasons of drought. Give them a thorough soaking of manure-water, and then mulch with half-decayed manure or leaves; and if dry weather prevails, examine the border thoroughly in 14 days after, and if dry, and inclined to crack, give another watering. Of course this should be discontinued when the Grapes are ripe, adding slightly to the mulching the last watering.
Vines in similar borders should not be neglected after the fruit is all cut. Many Vines are semi-starved in dry seasons after the fruit is cut. Keep the border moderately moist, so as to keep the foliage healthy till rain comes. Keep ripe Grapes cool and airy, and examine the foliage; and if any red-spider exists, get rid of it at once. Dryness at the root and red-spider generally go hand in hand, and are both very injurious to Vines, inasmuch as under their influence the foliage gets destroyed, falling off prematurely; and the result is seriously exhibited the following year. Examine Grapes intended to hang through the winter, and that have been thinned a short time ago, and if they appear too thick of berries, remove them at once. Bunches that get what is called jammed when fully swollen never can be kept successfully. To keep Grapes well over winter they should be thin enough to allow every berry to be exposed to the air. Young Vines planted this season should be encouraged to make as much foliage as there is room without crowding, unless it be supernumerary Vines planted with the view of giving a crop next year, which should not be allowed to make more than one or two lateral leaves, and the main stem should be stopped about 2 feet beyond the length to which it is to be fruited this season.
We have planted a quantity of the later class this season, struck from eyes in spring, to be fruited in 1874, placing two in the centre of each 6-feet light, one of which is allowed to run to the top of the house before it is stopped; the other is stopped when little over half-way up the roof. The former will crop the top, and the latter the bottom half of the roof next year, where one Vine 22 feet long would not do so satisfactorily. It would break very strong at the top, and very weakly at the bottom; but by planting two, as described, the whole length of roof can be cropped without planting in the centre of the house, as is common, and where Vines are in the way more or less. Vines planted last year, and to be fruited next, should not be allowed to make a rambling lateral growth, or the fruiting-buds will be defective. Two leaves to a lateral is sufficient. Pot-Vines intended to be fruited next spring should now be strong, and changing to brown at the bottom. Do not allow these to make lateral growths, except a few at the top, to prevent the main eyes from starting.
Give them a good supply of manure-water, and full exposure to light, so as to make sure of strong, well-matured canes.