154 



VEGETABLE FORCING 



than another, as shown by larger and better crops. 



(3) Uniform distribution of water. A system which 

 does not distribute the water evenly over the entire area 

 of the beds cannot give the best results. 



(4) Effect on soil. Some systems of watering compact 

 the soil, and cause the formation of hard incrustations 

 on the surface of the beds. This effect is objectionable 

 because it prevents the proper aeration of the soil and 

 necessitates frequent tillage to break up the crust. 



(5) Mechanical injury to the plant. This may occur 

 if a stream of water is forced against the plants through 

 a nozzle which is not properly adjusted. 



(6) Labor cost. This factor should have special con- 

 sideration. It is inefficiency to devote hours or days to 

 work which might be accomplished by means of me- 

 chanical devices that require very little attention. 



Watering can and hose. In the early days of green- 

 house cropping, all of the water was applied with water- 



, , ing cans. It is a 



slow, laborious 

 method that 

 should not be 

 used in any com- 

 mercial estab- 

 lishment, except 

 in starting small 

 lots of plants. A 

 step in advance 

 was made when 

 the hose was at- 

 tached to the 

 spigot, and water 

 applied direct to the beds. Some growers use the hose 

 without any nozzle, and this may be desirable if profuse 

 watering is necessary, as during the summer months 

 when cucumber plants have attained full development 



Fig. 52. A convenient form of nozzle 

 for greenhouse watering. 



