THE PRINCIPLES OF CULTIVATION 223 



be repaired by more waste in the shape of copious waterings 

 whenever a dry spell comes. Watering, however, cannot always 

 be avoided, but whenever necessary it should be thorough ; a 

 little sprinkling only brings up the capillary film of subsoil water 

 to the surface and increases the loss to the soil in consequence 

 what is necessary is a good soaking to renew the stock of subsoil 

 water. Then a mulch should be strewn over the wet ground or, 

 on the next day as soon as the surface is dry, the hoe should be 

 set to work to establish a soil mulch and save the water that 

 has been added from evaporation except by way of the plant. 



One last point in connection with management calls for a 

 little discussion of principles, and that is the protection of some- 

 what tender plants against frost. The actual degree of cold 

 attained in this country is rarely in itself sufficient to kill a plant 

 like a Tea-Rose, the plant does get killed sometimes, but it is 

 by drought rather than by cold If there is a covering of snow 

 to keep the plant in a moisture-laden atmosphere (and even at 

 temperatures below the freezing-point snow is always evaporating 

 and giving off moisture) the plant rarely suffers, however low the 

 temperature may sink. Below the snow the plant remains sound, 

 but the real mischief is done when a strong drying wind blows over 

 a frozen ground unprotected by snow. When the soil is at or 

 near freezing-point the plant's roots cease to take in any water, so 

 that if evaporation is at the same time going on from the surface 

 of the stems and branches there is nothing to repair the loss, 

 and the plant may dry up completely and be killed. In the 

 same way the sun is said to hurt a frozen plant by thawing it 

 too quickly ; it is not the thawing that does any harm, it is the 

 additional drying effect of the sun when the plant is already 

 almost without sap, and when the roots are still too cold to 

 bring in any water from the soil. In protecting plants for the 

 winter the great thing, then, is to shelter them as much as 

 possible from the drying effects of the wind ; plants cannot be 

 made appreciably warmer, however much they may be wrapped 

 up, but wind screens made of spruce branches, bracken, even dead 

 leaves and loose straw, will check the dangerous evaporation 

 caused by either wind or sun. If the conditions get very bad, or 

 if a cherished plant still unprotected gets frozen and the sun 



