6oo Journal of Agriculture . [lo Sept., 1910, 



Sulphate of Iron Treatment. — Many ingenious methods have been: 

 devised, by means of which a few days or even weeks in the commence- 

 ment of active growth may be postponed. It has been noticed that the 

 acid sulphate of iron treatment against black spot delays the st irting of 

 the buds and its application has thus a dual effect. 



Ground Condition. — Keeping the vineyard clean and free from weeds 

 and avoiding cultivation of the soil at the time frost is to be feared serve 

 the same purpose. Weeds and freshly moved soil evaporate moisture 

 actively and thereby accentuate the fall of temperature. It has even been 

 recommended to roll the ground, it having been proved experimentally that 

 such treatment causes the soil to lose several degrees less heat than if left 

 lumpy, owing to the lesser surface exposed bv the rolled land. 



Direct Measures. 



Several direct means of combating frost have been employed with more 

 or less success. Chief among these are direct heating, smudge fires or the 

 use of .smoke, and irrigation. It is not proposed to say anything here about 

 the straw, cardboard, or other movable shelters, which in some parts of 

 Europe are extensively employed, nor the use of white powders, lime 

 washes, &c. Their cost and the amount of labour they necessitate render 

 them unsuited for Australian conditions. 



Direct fieating. — At first sight, it might appear that the simjilest and 

 most logical method of fighting frost would be by direct heat from fires, 

 and yet, until recently, this method does not appear to ha\'e been trietl, or 

 even thought of. Smudge fires and protection of various kinds have been 

 recommended and practical use has been made of them since the remotest 

 times, but it is to our American cousins that we have to look for the 

 practical application of direct heating, as a method of fighting frost, and 

 with them its u.se on a large scale appears to be quite recent. Even in 

 France, many districts of which are frequently devastated by disastrous 

 frosts, I have ne\"er heard of recourse being had to the direct heat from 

 fires. It is onlv indirectly, as a means of producing smoke, that fires are 

 ever referred to. Direct heating seems to be a comparatively recent intro- 

 duction in America, and to be the result of a disastrous frost in the 

 orchards of the State of Colorado in the spring of 1907. In the following 

 spring, a few orchardists adopted what are now largely used under the 

 name of orchard heaters or fire pots, in order to avoid a repetition of the- 

 catastrophe. The success was such that their use has become very general ; 

 so much so that in 1909 hundreds of thousands of heaters were employed 

 for protection against frosts on the Western Slope. Various types have been 

 patented, some burning oil. others coal or charcoal. The writer is indebted 

 to Cr. \\'. H. Lloyd, of Mil dura, for prospectuses of several different types 

 of orchard heaters. The following details as to oil heaters are taken from 

 the advertising booklet of the Denver and Rio Grande Railroad, publi.shed" 

 in 1908 : — 



The oil burning orchard lieater costs about 22 cents (iifi.), and it takes 100 of 

 them to each acre. It is a pot of sheet iron, about the size of a ten-pound lard 

 bucket ; a lid of sheet iron slides across the top. The fruit-grower . . . places 

 one in every sj)ace between the rows of trees. A gallon of crude oil is put 

 in each heater and a small lump of waste floats on top of the oil, serving as a wick. 

 The height of the flame can be regulated by sliding the cover open or nearh- closed. 

 , . . Soon after lighting. . .vapour pours out . . .and mixes with the air 

 in burning, producing a large volume of heavy warm vapour. ... By keeping 

 up the fires the orchard can be kept above freezing point, even through an outside 

 temperature of 20 degrees F. The cost of equipping an orchard with the heaters is 



