12 BULLETIN 1435, U. S. DEPARTMENT OF AGRICULTURE 
as Silver Cluster), Marsh, Walters, and Duncan. The principal 
tangerine is the Dancy, although a few King are found, and recently 
the Temple, a new variety, is receiving some attention by growers. 
The part of the total acreage to be planted to each kind of fruit 
must remain largely a matter of personal preference. This study 
indicates, as discussed more fully later, that the kinds of fruit that 
led in net profit per acre were tangerines, oranges, and grapefruit, in 
the order named, but this relation may not necessarily always hold 
good. For example, a marked increase in the acreage of tangerines 
might result in a production in excess of the demand at present prices. 
A very important matter to consider before buying trees is that of 
rootstock. In most of the Polk County district the soil is high pine 
and is more favorable to the growth of trees if they have been budded 
to rough lemon stock. Many groves that were set 10 or 12 years 
ago on the high pine land have, here and there, a tree of dwarfed and 
peculiar characteristics, because the grower was unfortunate in 
getting a few trees that were budded on the sour orange or other 
rootstock not suited to this high pine land. Many growers have 
removed the undesirable trees and have replanted with trees having 
the rough lemon root. Such replanting gives the grove an uneven 
appearance and is a direct loss to the grower not only in the expense 
of grubbing out the old trees and replanting new ones, but in the 
loss of producing power of the grove. When necessary to replace 
trees, some growers consider it a more desirable practice, where 
possible, to purchase and reset trees similar in age to those in the 
erove. Ina short time, the grove assumes a normal appearance and 
is in condition to produce regular crops. 
NUMBER OF TREES TO THE ACRE 
The number of trees that should be planted to an acre of ground 
has been and will continue to be a much-debated question. The 
analysis of this phase of the development, as brought out in the dis- 
cussion elsewhere in this bulletin, would seem to indicate that there 
is justification in planting trees rather close in comparison with what 
is regarded as normal practice. In Table 7, showing the cost of 
development per acre, 64 trees per acre were considered because that 
figure represents the average for the groves under consideration in 
this study. It is believed, however, that 80 or more trees should be 
planted with the object in view of getting the income from the addi- 
tional trees until such time as crowding makes it necessary to remove 
some of them. There would be some additional development expense 
per acre in any provision for additional trees, in the cost of the extra 
trees, planting, and, later on, the quantity of fertilizer above that 
shown for normal requirements on 64 trees per acre. 
COST OF DEVELOPING A CITRUS GROVE 
The cost figures here used apply only to Polk County. Conditions 
vary a great deal throughout Florida and to a considerable extent 
throughout Polk County with respect to development costs. 
The figures cover conditions as they were found during the later 
years of the survey, that is, from 1919 to 1922, inclusive. They 
represent a fairly large number of observations, but even so they 
might be subject to many changes in the different items of cost. 
