VITICULTURE.

New Zealand Journal of Agriculture, Volume XVIII, Issue 5, 20 May 1919, Page 305

VITICULTURE.

By

S. F. ANDERSON,

Vine and Wine Instructor

THE COOL VINEHOUSE.

The vines are now entering on their rest period. Ventilators should be left open night and day, as frosts will do no injury at this stage, and the drier the atmosphere the better. Should the vine-borders on examination show extreme drynessthat. is, approaching a dusty condition a soaking may necessary. The dry autumn experienced in a large portion of the North Island may have reduced the vineborders to an exceptionally dry condition. It might be questioned why indoor-grown grape-vines should suffer from want of water any more than those in the vineyard. It is because conditions under glass are more artificial, and to permit-. extreme dryness means more or less of a

check. The effect of lack of water on a plant is exemplified in the extreme case of miniature plants, such as those shown by the Japanese, which are produced mainly by being kept at nearly starvation-point as regards water. The better the vine-borders have been made the safer they are from extreme conditions of moisture and dryness. Good drainage allows the get-away of - excessive moisture, but also provides for that capillary attraction of moisture during periods of drought. Pruning should not be commenced until the leaves have all fallen. It may be instructive at this period to quote Sir J. D. Hooker. He writes, " The death and separation of the leaf previous to its fall from the parent plant are not accidental, but due to the following causes: First, and chiefly, because there is developed at the base of the leaf or its stalk (if it has one) a transverse layer of cells which die after the leaf has performed its functions, and thereby produce their separation. The leaf consequently falls off, leaving a clean scar. Secondly, because the leaf rapidly acquires in spring its full size, whilst the branch on which it grows goes on thickening ; consequently the tissues at the point of union tend to become disunited. Thirdly, because the fluids contain earthy matter, much of which is deposited in the leaf-tissues, thereby preventing them performing their functions and hastening their death. This is proved by burning spring leaves, which yield but little ash, while autumn leaves yield relatively more even than wood. It is further remarkable that the substances contained in falling leaves are those which have ceased to be of value to the plant. The starch and protoplasmic substances, together with the most important mineral matters, such as phosphoric acid and potash, are transferred to the permanent parts of the plant before the leaves fall/ This quotation is made especially for the information of those who prune before the natural fall of the leaf with the mistaken view of “ plumping up the buds.” We can assist nature, but not by unnatural methods.