WA TER1NQ. 351 



Weeding ponds, rivers, and artificial waters, in garden and park 

 scenery, is often very expensive from its being necessary to empty and 

 clean out the bottom and sides of the excavation. Much of this 

 trouble and expense might be rendered unnecessary in many cases by 

 mowing over the weeds in the bottom of the water, when they first 

 make their appearance there in early spring, and repeating the opera- 

 tion at short intervals till the roots are destroyed from the want of 

 elaborated sap sent down by the leaves. 



Watering. 



Water, whether as a source of nutriment or as a medium of effecting 

 various other objects, is one of the most important agents of culture. 

 A certain degree of moisture in the soil is essential to the existence of 

 plants ; because no food can be absorbed by the roots that is not held 

 in solution by water, and because the decomposition of water, and its 

 perspiration from the leaves and bark, are continually going forward. 

 Plants require a certain degree of moisture at their roots, not only 

 when in active growth, but when in a state of comparative rest, 

 because even then perspiration is going on from those parts which are 

 above the ground, and from the roots themselves when plants are 

 taken up for transplanting. In the season of growth the demand for 

 water is greatly increased, and it diminishes as the period of growth 

 declines, and the power of decomposition and evaporation ceases. If 

 water in excess is given at this period of the growth of a plant, its parts 

 become distended in consequence of the absorption by the spongioles 

 still going on, while the power of decomposition and perspiration by 

 the leaves is diminished ; it becomes sickly, its leaves assume a yellow 

 colour, and if the excess of water is not soon withdrawn from the soil, 

 death ensues. By pulverizing soils and increasing their depth, their 

 capacity for holding water is increased, while by underground drain- 

 ing it cannot be retained in excess. By these means, and by the addi- 

 tion of manure acting mechanically and keeping the soil open, a great 

 facility is afforded to the extension of the roots, and the vigour of the 

 plants is increased in proportion, but at the same time the power of 

 the roots to exhaust the soil of water becomes greatly increased. If 

 under such circumstances a proportionate supply of water is not 

 afforded at the proper time, either by nature or art, the growth of the 

 plant will fall much short of what it might be ; of which examples 

 may be seen both in garden and field crops, by comparing the crops 

 of a moderately wet summer with those of a very dry one. It may 

 be concluded, therefore, that the full benefits of stirring the soil, 

 draining, and manuring, cannot be obtained without a command of 

 water. 



The specific purposes for which water is used in horticulture are 

 numerous. In general it may be applied wherever a stimulus is 

 wanted to growth, unless indeed the soil be already sufficiently moist. 

 It is given to newly- sown seeds, or newly -plan ted plants ; for the pur- 

 pose of setting blossoms, swelling fruits, increasing the number and 



