MULCHING, SHADING, AND WATERING. 151 



the atmosphere, and easily permeable to the roots of 

 plants in search of it. 



As the plants increase in size, the ground is shaded by 

 their foliage, which, in a measure, prevents the growth of 

 weeds and protects the surface of the soil from being hard- 

 ened by the sun. At this time hoeing is less required, nor 

 can it be performed without considerable mutilation of the 

 branches and larger roots, and thus cutting off in part their 

 communication with the soil injuries from which plants in 

 an advanced stage of growth, and under the burning heat 

 of summer do not readily recover. 



It is not fully decided whether the soil should be fre- 

 quently stirred during droughts. Our present opinion is, 

 that in all warm climates it should, at such times, be un- 

 disturbed. If the earth be already loose and in fine tilth, the 

 air that enters into its pores will deposit its moisture there- 

 in. At night the dews are deposited much more heavily 

 upon freshly dug soil. But this deposit of atmospheric 

 moisture will avail little if the surface is often stirred, as 

 more water will be given off by day than is absorbed at 

 night ; and a plot frequently hoed during a drought would 

 at length become quite dry to nearly the depth it was cul- 

 tivated. However it may be in England, here no deposit 

 of moisture from night dews, or supply brought up by ca- 

 pillary attraction from beneath, can make good the loss of 

 water by evaporation from the soil in a hot summer day. 

 De Candolle says that in most hot countries frequent hoe- 

 ings are avoided, as they really have the evil of favoring 

 evaporation of moisture from the soil at the time when, the 

 heat being most intense, the water is naturally retained 

 therein by the hardening of its surface, and would act with 

 most activity, in decomposing and dissolving the organic 

 matters it contains. The true course is deep, thorough cul- 

 ture early in the season and while plants are young. But 

 hoeing must not be performed in spring or autumn, at times 

 when the indications are that frosty nights will follow, as 



