This section is from the book "The Gardener V3", 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.
Keep ripe Grapes cool with a dry atmosphere. If our former directions regarding mulching and watering inside borders have been carried out, there is not much fear of the soil becoming dry and cracking before the grasses are all cut. Keep a sharp look-out for red-spider, and should its presence be detected, attack it with a sponge and soapy water. As soon as the crop is all cut from pot-Vines, turn them out, thoroughly clean the house or pit, which can either be devoted to Melons or young growing Vines in course of preparation for forcing next season. All vineries where Grapes are swelling off should now be shut up early, causing the thermometer to run up to 85° or 90° for a time, at the same time damping the whole floor of the house. At 6 p.m. put an inch or two - according to the weather - of air on the front. Black Hamburgs should now have no more fire applied than is sufficient to prevent the temperature from falling below 65° at 6 a.m.: Muscats should have 5° more. All advancing will now require constant attention in the way of stopping, tying down, and pricking lateral growths as soon as they appear.
Admitting that all Vines should not have their main stems closer than 3 1/2 feet, in stopping the fruit-bearing shoots leave them of sufficient length to cover the whole space without crowding. Indeed, we prefer that the rods be 4 feet apart, and the whole space taken up with foliage. The close pinching system has a debilitating effect on Vines, and they cannot carry heavy well-swelled crops without ample foliage. Thin off superfluous bunches of all certain-setting varieties when the Vines are stopped. Less free setters should not be finally thinned either in bunch or berry until it be seen which bunches have set the best. As a rule, however, it is a waste of energy to allow the berries to grow to the size of Peas before they are thinned. Such varieties as G-ros Colman and Duke of Buccleuch should be freely thinned so as to give room for their large berries to swell without being jammed.
Vines planted early in March will now have got a good hold of the border, and may be encouraged with a higher temperature. In training those that are intended for the permanent Vines, and which will be cut down next season, allow them to produce all the foliage that can be trained to the trellis without crowding. Others, intended for bearing next season, and afterwards to be cut out, should have their laterals stopped for the present at the second leaf, and the main rod stopped when half-way up the roof, and afterwards allowed to grow on for a time. All covering of litter and leaves that have been applied to outside borders should be removed, not all at once, but partially about the middle, and wholly at the end of the month; and then let the border be forked up, without, however, disturbing the roots, and put 2 or 3 inches of good manure on. It is a great mistake to suppose that Vines do not require feeding after the fruit is cut in May. The next crop depends much on the foliage being kept healthy as long as possible, and the Vines being fed properly, as long as the foliage continues healthy.
Pot-Vines will now be ready to go into their fruiting-pots. In potting them use a good holding maiden loam, some bone-meal, or Standen's manure; place them in a light house, and grow on with a warm, genial atmosphere, giving a good supply of air on all favourable opportunities.