FROST PROTECTION. 345 



leaves, citrus trees are in a much better condition to with- 

 stand cold than when they are starved, or only poorly 

 supplied with food. A sufficient supply of nitrogen to 

 give a healthy, dark green color is essential. The trees 

 must not be over-stimulated, however, else the sappy, im- 

 mature wood formed, will suffer severely ; but a sufficient 

 supply of well-balanced food should be available to keep 

 the trees in a healthy condition. A starved condition is 

 analogous to a diseased state. Nitrogen must not be sup- 

 plied in excess of other elements, but it will prove to be 

 poor policy to reduce the amount, in the hope of keeping 

 the tree dormant, so as to interfere with the normal devel- 

 opment of the branches and leaves. 



Dormancy as a Factor. Unfortunately, the citrus tree 

 is not distinctly periodic in its growth. It responds readily 

 to short periods of warm weather ; the sap starts to flow ; 

 the buds commence to swell. In this condition it may be 

 severely injured by a comparatively high temperature. 

 In a perfectly dormant condition, citrus trees will with- 

 stand a very considerable degree of cold. How many de- 

 grees more of cold a tree will stand when dormant, than 

 when not dormant, cannot be definitely stated, but the 

 difference is very appreciable. Practices or treatment of 

 the trees having a tendency to start growth during the 

 danger period, should be promptly discontinued. Among 

 these may be mentioned, heavy pruning and fertilizing 

 and tilling the soil too early. 



FERTILIZERS AND CULTIVATION IN RELATION TO 

 DORMANCY. 



Heavy applications of nitrogenous fertilizers followed 

 by cultivation have a tendency to start growth in the trees. 

 As a general rule cultivation should not be commenced 



