Chapter Fourteen 

 BALANCE OF ROOT AND SHOOT 



For the plant lover this is the most important principle 

 in the entire book, since it might be considered a summary 

 of all the principles of plant growth, but at the same time it 

 is also the most difficult to understand fully and to control 

 properly. The balance is one of function rather than struc- 

 ture, but it is actually a true balance. It will be recalled that 

 the function of roots (Chapter 5) is the absorption of water 

 and mineral salts, and the functions of the shoot (leaves and 

 stem) are the manufacturing and conduction of food (Chap- 

 ters 8 and 11). Conditions do not remain constant and 

 therefore the balance cannot be perfect at all times as might 

 be illustrated by the absorption and loss of water. A perfect 

 balance of this function would mean a steady rate of absorp- 

 tion and a parallel steady rate of transpiration. As has been 

 pointed out, transpiration is several times faster during the 

 day than during the night while absorption is more nearly 

 uniform. The balance of importance and interest is rather 

 one which will result in a normal growth. 



In nature a healthy plant will maintain a balanced root 

 and shoot for the average conditions of the habitat. This 

 results in a steady growth of plant and a large number of 

 seeds for reproduction, but often they are smaller in size 

 than desirable for edible varieties. Natural plant growth 

 requires a top of such size that an abundance of food can be 

 made for seed formation, in order that the species may repro- 

 duce itself. In gardening, however, there are many cases 

 where we get a more desirable result with a disturbed bal- 

 ance. We may prefer soft tender shoots of many of our vege- 

 tables, or fewer but larger flowers or fruit, which can be had 



92 



