SEASONAL ORCHARD WORK

Mt Benger Mail, 19 October 1938, Page 2

SEASONAL ORCHARD WORK

By 18, FREW, Esq., OrehaM Instructor

, y Grafting The present time is the most suitable for the grafting of apples, and even stone-fruit will take fairly readily at this period. The essentials for satisfactory grafting are first and foremost, a supply of suitable grafting wood, which has been kept fresh and dormant by having been procured during the winter -and buried in the ground for preservation until the present time. The second essential is an exceptionally sharp knife. No satisfactory cuts can be made unless thp knife blade is keen. Thirdly, ■ft suitable grafting wax is necessary. Far a satisfactory union, all cut surfaces must be. perfectly sealed to exclude air and consequent drying out of the scion. The old formulae for grafting wax of a mixture of beeswax and resin, or cow-dung and clay, are not recommended these days, when a more satisfactory cover and resultant better union is established by the use of the petrolatum products either green crude petrolatum or light antber petrolatum. Both appear W b,e equally satisfactory. The last essential is a supply of raffia, for the tieing the graft. This material has proved moat suitable for the purpose, provided that it has been thoroughly soaked in water before use. When dry, it is far too brittle to work With. Types of Grafting.

These are numerous including some very crude methods, which are not practised. The two , principal methods now used are notch-grafting on the stump of the old tree, and grafting by various means on to the skeletonised framework of .the existing tree Ths former method enables a large number of trees to be worked over ir. the limited time available for this work, as perhaps only four or five grafts are necessary on each stump, but it entails a lapse of several years before the consequent new tree has grown to sufficient size to carry a crop again. The latter method is comparatively slow work, as perhaps a hundred grafts might be inserted in to the existing tree-frame, and it is unlikely that a, grower ’will find time to. dd mope than a small number pf trees in one season. The great advantage of this method, however, is that a full crop oan be expected from a full-sized tree in three years, and a partial crop obtained even in the second year after grafting. A compromise between these two systems is now being widely adopted. By heading the existing tree to a height of perhaps five feet, and inserting a reasonable number of scions on to the remaining framework, a larger 1 number of trees can be worked than with the complete re-furnishing system:, and a reasonable crop can be expected in three years. The Process Itself The actual grafting process is exceedingly simple. Provided clean straight cuts are made in both parent and scion wood, and that care is taken to ensure the cambium layer of both sections is touching, one can be reasonably assured of a satisfactory “take.” The necessity for a straight cut becomes apparent when it is realised that a “ripple,” or corrugated, cut must result in an intermittent contact and lack of contact, throughout the length of the cut, possibly ruining any chance of union. b}otch*g?aftiftg> the best method of grafting on the stump, is obtained by making a Vshaped cut in the bark at the top of the stump; the scion is then cut to fit the notch, and is tacked ifdo place, and waxed over. The most satisfactory method of grafting to the tree-frame is to use the whip or tongue graft. With this method it is necessary to leave young lateral stumps approximately l?in. apart on the skeletonised framework, and graft the scions to these, Failing this, a “peg” graft may be inserted into an oblique cut made directly into the leader. Further and more detailed instructions on this work may be had at any time, by communicating with the writer. Frost-Fighting The necessity for some means of prevention from frost damage is occupying the minds of an increasing number of orchardists in this district, and it is becoming more evident each year that frost fighting apparatus is practically a necessity in order to ensure crops. After years of experiments, investigators are now reluctantly compelled to realise that only one satisfactory method is known for frost prevention, and that is: heat. Saioke screens, flooding the ground, creating draughts of air, spraying the trees with water, have all proved to be ineffective. If the temperature falls, only one provision will save a freeze, and that is the raisin; ef the temperature. Fire-pots are therefore the only solution at the present time, and crude oil ue most satisfactory fuel as yet' known to use in them, For absolute safety, one fire-pot per tree is recommenced, although

except on an especially cold night, probably there would be no need to light more than half that number of pots. An automatic frost alarm is desirable, in order that growers will be warned in advance of when it will be necessary for them to start lighting up. To check the temperature, thermometers should be placed in various parts of the orchard, at a height of 4ft bin. from the ground. Lighting by means of a torch containing a 50-50 mixture of benzine and kerosene can be safely and rapidly carried out, and should be done by encircling the area to be attended to by lighting the outside ring of pots first, and graduallly working into the centre. In this way, the heated atmosphere will be concentrated, and the air in the whole block induced to rise more rapidly. Sufficient pots should be kept alight to maintain the temperature above danger-point. More than this is merely a waste of oil. Regarding the danger-point, 1. am indebted to Mr W. R. Lloyd Williams, Orchard Instructor. Alexandra, for the following information which may he accepted as a general guide only, to the temperatures which the various fruits will endure without damage, always provided that the temperatures which the various fruits will endure without damage has not been below 32deg. for a long period;— Temperatures (in degrees fahrenheit) endured for 30 minutes or less by deciduous fruittrees (unsheltered thermometers) are given respectively in order for:— a -“I g f. TJ ■© £g° a g W O 6D O « ° a m TS £ g s •S rZi 3 g deg. f. deg. f. deg.f. Apples .. 25 28 29 Peaches ‘. 25 27 30 Cherries ... 28 28 30 Pears .. .. 25 28 30 Plums .... 25 28 30 Apricots .. 25 28 31 Prunes .. .. 23 27 30 Almonds .. 26 27 30 Grapes .... 30 31 31 Walnuts (Eng.) 30 30 30 It will be seen that the temperatures endured vary somewhat between the different kinds of fruits, though in the main they are much the same for the more common stpne-fruits It is noteworthy that in the first column cherries are shown at 28deg. whereas other fruits are mostly at 25deg. f. This is definitely characteristic of the cherry—some have been lost in Central Otago thisi season through failure to light up at this stage. It is difficult to state Just when the danger period is over. However, it is quite definite that with stone-fruits the most dangerous period is just when the young green fruits have become fully exposed, before having a chance to harden up. From then on the danger lessens, though it still exists when more severe frosts occur.