This section is from the book "Commercial Gardening Vol3", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
A fortnight before the Vines are to be started a good watering is given if the borders are dryish. The house is shut up and kept close to induce the sap to begin to move. At the end of the fortnight the heat is turned on gently and another watering with warm water given; unless the Vines are being started naturally, when cold water will do at all times. The rods are syringed twice a day, and the best tool for the purpose is one of the knapsack sprayers, fitted with a Mistifier Junior spraying nozzle. This nozzle can be adjusted to give a jet very like a syringe, and the saving in time and the avoidance of the sloppiness of the syringe is well worth the outlay. To ensure the rods being thoroughly wetted the house is worked both ways. The night temperature at this time should be from 45° to 50° F., giving a little air at 70° F. during the day. As the Vines break, the spraying is discontinued on all but bright days, or the buds will sometimes rot out, and the night temperature is gradually raised to 55°. When all the buds are fully broken the spraying is discontinued, and the borders are damped down through a fine rose. As little water should be used as possible as long as the surface of the borders and the pipes are damped all over. This should be done every morning, and on bright days twice or three times according to the state of the air in the vinery, the last damping being given when the house is shut up. This should be done about an hour before the sun is off the glass. As growth proceeds the temperature is raised to 60° to 65° at night and 75° by day, with air being given at that temperature in mild weather. Cold draughts must be avoided; and the particular bugbear of the grower is an east wind and a hot sun, such as is often experienced in the spring. The only thing is to give just so much air as possible without draught, keep the pipes as cool as possible, and damp down frequently. As soon as the buds have broken, the rods are tied up into place, and any buds which are not required rubbed out, leaving the one nearest to the rod if possible, i.e. if it looks strong and likely to fruit well. When the laterals are long enough to show three leaves beyond the bunch they should be stopped at that point, and about ten days after be tied down. Private gardeners only bring the laterals down part of the way at the first tying, but the market man generally does it in one operation, and a careful man will do it without breaking out any laterals worth mentioning. Alicante is a bad variety to tie down, but if the house is wired as advised for it little difficulty will be experienced. The lateral, if difficult to get down, should be steadied at the base with the thumb and finger of one hand while it is gently bent down by the other hand. Sometimes by giving a gentle twist to a refractory lateral it can be brought into position quite easily.
Soon after the tying down is done the Vines will be coming into flower (fig. 382), and at this time the damping down must be withheld, except in the mornings of bright days, and the temperature must be raised at night from 65° to 70°, the temperature for Muscats being in all cases a few degrees higher. The rods should be tapped with the closed hand about the middle of the day to make the pollen fall and fertilize the fruit. Muscats want a little more attention in this way, and it is a good practice to go over the Vines with a very fine spray as the sun begins to rise, and then, when there is a nice chink of air on in the middle of the day, tap the rods as before. Canon Hall Muscat is very difficult to set well, but some growers have the knack of it. One method in use by a large grower is to get the temperature up to 90°, then go round the bunches with a soft piece of a boa or rabbit skin and gently pass it over each bunch that is ready, and follow this up with a light spraying of the bunches and a damping down of the border. The reason some grapes are shy of setting is because the stamens in those varieties fall away from the stigma (fig. 383, 6) before the pollen is shed; and it seems reasonable to suppose that any treatment that would make the stamens remain erect would be likely to ensure a good "set", and the moist heat generated by the spraying when the house is hot would cause the pollen which had fallen upon the stigmas to commence growth at once. After the blooming is over the damping down must be resumed, and the temperature may be reduced to what it was before the appearance of the flowers.
Fig. 382. - Young Shoot of Vine, showing position of Flowers.
During all the growing time of the Vines strict attention must be paid to keeping down all side-growths from the laterals - sub-laterals as they are called. These are stopped at one leaf, and the same every time they make fresh growth. If the leafage threatens to become too thick, they may be kept stopped altogether. All such growths are best stopped before they require anything more than the finger and thumb to take them off.