PROBLEMS OF PROJPAgATION. 



459 



There are two outstanding lines of practice suitable with or without 

 modification for individual plants and characterized by the manner 

 in which water is supplied and the temperature maintained. They 

 may be termed : 



1. Under-root watering in shade. 



2. Overhead watering in sunshine. 



The method in which under-root watering is carried out will be 

 understood by reference to fig. 168, which shows a section of one of 

 our propagating pits. The essential feature is a teakwood tank on 

 top of which is hinged a ' ' light. ' ' Along the bottom of the tank 

 runs a hot-water pipe 1^ inch in diameter coming off the main heating 

 pipes of the house and controlled by a valve outside the tank. A water 

 layer covers the pipe in the tank. Over the water a sparred frame 

 rests upon fillets fixed to the sides of the tank. Fillets at different 

 heights allow of the frame being placed closer to or further from the 

 surface of the water. Over the sparred frame crocks or slates are 

 placed, and then sand or fibre, whatever be the soil medium that is 

 used. The point of the whole is that the soil for cuttings overlies a 

 chamber containing water from which the soil is separated by a layer 

 of air. The water can be heated to a required degree by the water of 

 the heating system circulating in the 1^-inch pipe at bottom of the 

 tank, and the moisture rising from the surface of the heated water 

 ascends through the sparred frame and upwards through the overlying 

 soil. In this way the soil is kept moist and any required temperature 

 can be maintained by regulation of the valve. The water is replenished 

 by a filling tube. 



Cuttings in such conditions have their ends plunged in a moist 

 aerated environment from which they get all the water they require. 

 They are never watered overhead. 



This method is particularly adapted to plants with hairy and 

 woolly surfaces. It gets rid of the risk of surface decay that attends 

 overhead watering in such plants. Our arrangements so far have 

 only provided for striking cuttings in the shade, and the temperature 

 maintained is derived from the hot-water pipes. By regulation of the 

 valve the temperature can be varied — increased to give stimulus or 

 kept uniform. I believe the temperature condition is of paramount 

 importance. 



I The practice of striking cuttings by overhead watering in sunshine 

 \ is, I believe, borrowed from the French. I learned it from that fine 

 gardener, the Eev. Canon Ellacombe. The method is simply this — 

 I the cuttings are plunged in sand in an ordinary frame exposed to full 

 j sunshine and watered at short intervals, say every half -hour. The 

 , watering may be done automatically or by hand, but the latter involves 

 ] 'frequent opening of the frame. The soil temperature may rise to an 

 j intense degree, but fluctuates. A uniform temperature is impossible, 

 f For some plants it is more efficient than that of under-root watering in 

 j shade. The cuttings strike more rapidly. It is not good for plants 

 j with woolly and hairy surfaces, 

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