354 WATERING. 



atmosphere in which nature supplies water, the afternoon or evening 

 may be chosen, when the air is both cooler and somewhat moister than 

 during sunshine. As in soils that are stirred on the surface, the 

 greater part of the roots are always at some depth, the quantity of 

 water given should be such as will thoroughly moisten the interior of 

 the soil, and reach all the roots. A slight watering on the surface, 

 unless the soil is already moist below, will not reach the fibres, and 

 will soon be lost by evaporation. Such driblets do more injury than 

 good to plants ; for when in want of water the roots penetrate deep, 

 and under such circumstances a small quantity of water on the surface 

 checks the capillary attraction of moisture from below ; and thus the 

 roots that are grown deep, which are those on which the plant is made 

 to depend in times of great drought, are deprived of their supply of 

 water, and the plant exerts its eiforts to throw out horizontal fibres ; 

 by the time these fibres are formed, and the young shoots extended, 

 the supply of water on the surface again fails, and they are again 

 checked, and perhaps destroyed : thus the efforts of the plant being 

 uselessly exhausted between the two extremes of a supply and a defi- 

 ciency of water, it naturally declines in its growth, and hence arises 

 the general opinion that watering in dry weather injures more than it 

 benefits plants. Most water is required by plants that are in a vigorous 

 state of growth and have a large breadth of foliage ; least by those 

 which have nearly completed their growth ; and in general none by 

 plants in a dormant state, excepting in such cases as that of watering 

 grass lawns in summer to stimulate vegetation, or irrigating meadows 

 after they have been mown for the same purpose. In the case, how- 

 ever, of excessive dryness, some degree of moisture must be afforded 

 to such plants as are liable to become desiccated even though dormant. 

 Succulent plants, for example, will bear a great degree of dryness, 

 through a protracted period ; whereas others that perspire more through 

 the bark would be completely dried up if equally exposed to drought. 

 An excess of water to plants in pots, and especially to those having 

 suffruticose stems, such as the pelargonium, or to hair-rooted plants, 

 such as heaths, and to many bulbs, is extremely injurious, and often 

 destructive of life. In the first case more water is absorbed by the 

 roots than can be decomposed by the leaves ; in the second case the 

 roots are suffocated and rotted from their delicacy ; and in the third, 

 rotting takes place from mere organic absorption ; for when the leaves 

 of bulbs decay, their roots decay also, and consequently they cannot 

 absorb water by their spongioles ; while absorption by the tissue still 

 going on, the vessels become surcharged and burst, and the bulb rots. 

 Hence in the case of bulbs, and similar plants in pots, the soil in 

 which they are kept should contain no more moisture than what is 

 necessary to keep the bulb, tuber, or corm, in a succulent state ; but 

 in proportion to the dryness in which bulbs are kept at this season, 

 should be the abundance of the supply of water when they begin to 

 grow. All bulbs will be found to flower in their natural habitats, 

 either during or immediately after a rainy or moist period of the year, 

 its is the case with our wood hyacinths in spring, and with the colchi- 



