I 
FROST PROTECTION IN LEMON ORCHARDS. \) 
table shows that plats 1, 2, 8, and 10 were located in nonheated 
Lisbon orchards, while plats 4, 6, and 9 were in heated orchards. 
Plat 3 was located in a nonheated Eureka orchard, and plats 5 and 7 
in heated Eureka orchards. Plats 2 and 3, which are listed as non- 
heated, were partially protected by heaters in neighboring orchards. 
Plat 5, which is listed as a heated plat, was inadequately supplied 
with orchard heaters, as there was only one heater for every four trees. 
This plat was included for the purpose of comparing inadequate 
orchard heating with no heating and with adequate heating. 
METHOD OF SECURING RECORDS. 
The fruit from each individual tree at each picking was assorted 
into four grades, namely, Green, Tree-Ripe, Frozen, and Cull. The 
Green grade included all fruits which had either a dark-green or light- 
green color, and which, from outward appearances, were apparently 
sound. These fruits were expected after curing to constitute a first 
grade of valuable commercial lemons. The Tree-Ripe grade included 
the apparently sound fruits which had a yellow color. These fruits 
were usually considered to be of some commercial value. It was not 
necessary to cure them before shipping to the markets. The Frozen 
grade included all fruits which were seriously injured by the low 
temperature, as shown by their soft or partially dried-up condition. 
When there was any question or doubt as to whether the fruit was 
frozen or not it was cut open, so as to make an accurate determination 
before classifying. The Cull fruits were those which for some reason 
aside from frost injuries were unfit for the market. A frequent cause 
of Culls was decay of various kinds induced by mechanical injury to 
the fruits. Many of these injuries were brought about by punctures 
or bruises during the violent winds that accompanied the cold 
weather in January, 1913. 
After the assortment of the fruits from each tree the number and 
weight of the lemons of each grade were determined and recorded in 
special field-note forms, as shown in Table III. 
As lemons are usually picked to a certain uniform size with the aid 
of metal picking rings, no attempt was made to size the fruits, as 
would have been necessary with oranges or grapefruit. If desired, 
an idea of the relative size of the lemons can be secured by comparing 
the number with the weights of the fruits. 
Inasmuch as the frozen lemons began to dry out soon after the 
freeze, thus altering their normal weights, the data regarding the 
comparative sizes of the fruits secured in this way are likely to be 
somewhat unreliable. For this reason, also, in studying the effect of 
the freeze upon the production of the trees in the different plats, it 
seems desirable that most of the conclusions should be based upon the 
number instead of the weights of the fruits. 
140207°— 20— Bull. 821 2 
