INTRODUCTORY REMARKS 313 



the knuckles or with a stick, when a clear and unmistakable answer 

 will be obtained. Plants differ widely in their demand for water. 

 Some are very thirsty, others require less frequent attention. The 

 season of the year and the state of the atmosphere have also to be 

 considered, as well as the fact that a heavy soil is more retentive of 

 moisture than a lighter compost. A watchful eye and a willing hand 

 will seldom err on this point. The water should always be of the same 

 temperature as the house, otherwise the plants will be constantly 

 checked. A tank in the greenhouse meets this requirement. In its 

 absence, the watering pots should be kept full under the stage, and 

 they will be ready when wanted. 



In the open ground, it is better to water a few plots thoroughly for 

 two or three successive evenings, and then have an interval, rather 

 than moisten the surface daily. The effect of constantly applying 

 small quantities of water is to encourage the surface growth of roots. 

 Then if the sun shines fiercely upon the soil, the first day of neglect 

 results in immense mischief. 



DRAINAGE is easily managed. Into each pot put a crock almost 

 the size of the bottom, with the convex side upwards. There need 

 be no niggling to remove sharp angles, or to make the fragment 

 shapely. Cover this with smaller crocks, and these with moss, cocoa- 

 nut fibre, or in some cases with small pieces of charcoal. If the 

 compost has a proper admixture of sharp sand or grit, free drainage 

 will be insured, and yet the soil cannot be washed through the pot. 

 Silver sand is employed in districts near a supply, and there is 

 nothing better for the purpose. But road grit, and the sweepings 

 from gravel walks, finely sifted, are substitutes not to be despised. 



VENTILATION is important, for a house full of plants cannot 

 long be kept close with impunity. The lights should be opened 

 whenever the state of the weather admits of it, and by doing 

 this on the side opposite to the quarter whence the wind blows, 

 it is frequently safe to give air when it may be dangerous from 

 other points of the compass ; and it should be done early in the 

 day before the sun gets hot. Often the lights remain closed on 

 a sunny morning, until the atmosphere becomes stifling; and then 

 perhaps plants which have been made sensitive by excess of heat are 

 subjected to a killing draught. 



IN MANAGING TEMPERATURE, there should be no violent alterna- 

 tions of heat and cold, for these bring speedy disaster; and it is unwise 

 to employ more heat than is actually necessary. Deviations from this 

 rule are generally traceable to neglect. If the proper season for 



