FROST PROTECTION IN LEMON ORCHARDS. 
19 
MUHBtfi 
effect of even a small number of heaters in an orchard, but also 
presents strikingly the value of efficient heating in orchards, as the 
number of merchantable fruits produced during the 
year 1913 in the adequately heated orchard is much 
greater than that produced in the partially heated one. 
Table XV shows the percentages of fruits by 
grades for each picking during the calendar year 
1913 in the nonheated plat 1, an acre of Lisbon lemon 
trees, as compared with the heated plat 4. The 
percentages of frozen and merchantable fruits in 
these plats are shown graphically in figure 9. A 
study of this diagram shows that in the heated plat the 
percentage of merchantable lemons during February 
was 76, 
while 
in the 
n o n - 
heated 
plat 
the 
p e r- 
cent - 
age of 
merchantable fruits was zero. At no time during the calendar year 
did the curve of merchantable fruits in the heated plat fall below 
the curve of the same class of fruits in the nonheated one. Cor- 
respondingly, the curve of the frozen lemons shows a relatively 
higher percentage during all the pickings up to October in the non- 
heated orchard, as compared with a low percentage of this class of 
fruits in the heated one. 
3 yv.Eirc/fAiA/rAei.f f/?t//rs 
/vor ftsAreo 
r£-e. 
/laa 
Fig. 8. — Diagram showing the niimber of frozen and merchantable fruits produced on plat 3, 
a nonheated acre of Eureka lemon trees, plat 5, a partially heated acre of Eureka lemon 
trees, and plat 7, an efficiently heated acre of Eureka lemon trees. The figures here shown 
are taken from Tables VII, IX, and XI, respectively, which give^the estimated production 
by grades for each month's picking for these plats during the calendar year 1913. 
Table XV. — Percentages of fruits by grades produced in the nonheated acre of Lisbon 
lemon trees, plat 1, as compared with the heated acre, -plat 4, during the calendar year 
1913. 
[These percentages are computed from the total number of lemons produced by these plats as shown in 
Tables V and VIII.] 
Grade and condition. 
Date of picking. 
Feb. 14. 
Apr. 7. 
May 14. 
June 24. 
Aug. 11. 
Sept. 12. 
Oct. 26. 
Dec. 12. 
Green grade: 
Not heated 
Heated 

43.35 

32.81 

76.16 


100 
23.84 
12.77 
60.08 
5.66 
19.26 
18.43 
79.34 
1.54 
8.03 
80.04 
12.63 
28.67 
67.24 
3.67 
18.10 
32.34 
85.34 
3.67 
9.72 
63.99 
4.94 
42.35 
68.80 
21.57 
26.20 
63.92 
95.0 
14.57 
2.65 
21.57 
2.35 
31.76 
35.22 
37.65 
56.81 
69.41 
92.03 
27.06 
7.45 
3.56 
.52 
15.46 
29.83 
55. 67 
64.64 
71.13 
94.47 
11.34 
4.42 
17.53 
1.11 
44.0 
54.28 
24.0 
25.0 
68.0 
79.28 
32.0 
20.72 


95.28 
99.30 
Tree-Ripe grade : 
Not heated 
Heated 
.41 
.70 
Merchantable fruit: 
Not heated 
Heated . 
95.69 
100 
Cull grade: 
Not heated 
Heated . . 
4.31 

Frozen grade: 
Not heated 
Heated 


