Fighting Frost

Hawke's Bay Herald-Tribune, Volume 81, Issue 18, 14 October 1937, Page 9

Fighting Frost

THE COST TO H.B. GROWERS How to Secure the Best Results USE OF OIL POTS Methods of combating frost in Hawke's Bay orcbards and the costs involved , in carrying-out protective work of this nature is dealt with - in the following statement snpplied by Mr J. H. Milhe, president of tlie Hawke's Bay Fruitgrowers' Association, on behalf of his executive. "As some j)ublieity lias recently been given in the Herald-Tribune to the matter of the efficacy and cost of frost fighting, my committee has requested me to place before the public generally, and fruitgrowers in particular, a few. considered facts — not with ,a view to controversy but solely with the idea of assisting those who liave recently equipped themselves for the fight, but who, from lack of experience, may, by overlooking certain points, obtain les* protection than they otherwise would,'' states Mr Milne. "The matter of cost, too, is oni» whieh has been raised, and which wc have dealt with very carefully ; and the following figures, based upon what is requircd to protect a 10 acre orchard, may be taken as reliable. "It will be readily understood that the larger the block of orchard to be protected, the fewer will be tho %umber of pots required per acre, and it is generally agreed that for one single acre, 100 pots are needed, whih' for 10 acres, about 60 per acre would be sufficient. "Details of cost would thus be a> follows: — 10 acres at 60 pots per acre — 600 pots at 2/ — £60. "These pots should last at least 4 years, so the annual outlay may be taken as £15. Assuming that the firing is done on only one night of the year, cost would work out as follows* Outlay on 600 pots 15 0 0 Six hours burning (say 2 gals. oil per pot) at 8.21d per gal. 41 10 Four men at 14/- 2 16 0 £58 17 0 "If frequent firings have to be inade the first item would be divided by the number ot such firings and cost per burn would he proportionally reduoed. . "There Is no doubt whatever that a considerable rise in temperature can be obtained by the proper use of fire pots, and the chief causes of failure may be traced to one or inore of the following;— 1. Delaying too long before iightfng up. * * 2, Insufficient pots. . • 8, Unwise placing of pots. 4, Allowing fires to go out to6 soon "We would suggest to our growers tbat, if the temperature has been allowed to drop below danger point before ligbting up, pots be allowed to burn full blast until thermometer shows a definite rise, then dampers (either lids or spreaders ) should be used to control the ttunperature throughout the night. For anyone who is sceptical, one instance, actually ohserved, may be quoted. A 4-acre block of* stone fruit, provided with 300 oil pots, was fired on the night of the rccent heavy frost, and the temperature raised to 34 degrees while outside the reading was 24.5 degrees. "Regarding item 3 above, it is good praetice to provide one pot per tree ' round the outer rows of , block to bo fired, thus i'orming a Barrage through wbich the frost dril't cannot penetrate, "Heat should be lnaintained right up to sunrise. Don't "spoil the ship for a ha'porth of tar,» but keep fires going until the sun's warmth begins to a ssert itself. "If possible, have more than one thermometer. Keep one outside the infiuenqe of the fires for checking purposes. but use at Jeast one in the block you are proteeting and, by frequently . consulting it, adjust your fires to maintain a steady and safe temperature. "Growers should i'orm groups and keep in toueh with one another during the night. This will give them confidence and also assure that their observations are verified. "With reference to torches for ligbting up, no very elaborate or expensive articles are required. We suggest a bottle provided with a eheap sprinkler stopper, and »a toreh ' consisting of a piece of pumice soaked in kerosene and held by a wire. 'A'. goes ahead and 'llicks' a little benzine from the bottle and 'B' follows and applies the torch. The pots can thus be lit almost as quickly as one can walk. "The care of pots is also an important item — especially with the cheaper kind. Oil should be1 used liberally on the outside of these before they are placed in position and certainly before they are stored after the danger of frosts is past. Care in this direction will prolong their lives and thus ecouoiuise the general costs of frost fighting."