The Garden Under Glass

I62 THE GARDEN UNDER GLASS Stoning and Colouring After the bunches have been thinned they will swell rapidly for a few weeks and will then remain at a standstill for some time, during which the stoning takes place. At the time of flowering, of stoning and of colouring it is inadvisable to defoliate the vines greatly, or it will cause an undue flow of sap to the bunches. As the summer ad vances more air will be needed from both top and bottom ventilators and closing the house may be delayed until four o’clock. Once the first tinge of colour is seen a little air may be left on at nights, and as the colour deepens so may the amount of air be increased. At this period also the amount of moisture in the atmosphere will need to be diminished by damping less frequently until it becomes totally un-necessary. On no account must the vines suffer from lack of water at the roots, but it is unwise to flood them with water during flowering, stoning and colouring. Ventilating a Vinery For the purpose of greater clearness I may perhaps spare a few special words on ventilation, which requires a certain amount of experience, and in April a considerable amount of patience. A start must be made at the time when the house is closed for the purpose of causing the vines to break into growth. For beginners it is better that the thermometer be taken as a guide. With experience the smell of a house will suggest to the gro wer the need of air. The starting temperature of a vinery has been shown to be 45° to 50°. In the daytime a spell of sunshine may raise the temperature,