38 VEGETABLE FORCING 



erecting the frame, and water should be kept out of the 

 joints by the frequent application of thick paint. 



Beds and benches. Formerly vegetables were grown 

 almost entirely on benches, but benches are seldom seen 

 in the large modern greenhouses used for vegetable 

 forcing. It is argued by some that better results are 

 obtained with benches, and there are doubtless instances 

 in which this is true, but the disadvantages so far over- 

 balance the advantages that benches should seldom be 

 given serious consideration, except for midwinter forcing 

 of warm crops and for sub-irrigation. Among the disad- 

 vantages of benches for vegetable forcing may be men- 

 tioned (1) the cost of construction ; (2) the cost of 

 repairs ; (3) interference with the operations of handling 

 the soil and manure, and of spading, plowing and harrow- 

 ing, thus increasing the cost of production ; (4) the soil on 

 the benches dries out much quicker than the solid ground 

 beds ; (5) more skill is required in watering the soil on 

 benches, unless sub-irrigation is employed. 



In the modern greenhouse devoted exclusively to vege- 

 table forcing there is no necessity either for benches or for 

 sides to the solid beds. The whole area under glass is 

 regarded simply as one unbroken plat which, with the 

 exception of the necessary walks and alleys, may be cul- 

 tivated with as much freedom as outside gardens. When 

 benches are regarded as essential, they should be made of 

 durable material. Concrete is becoming especially popu- 

 lar. The construction may be of separate blocks ; or the 

 benches may be made with a \ l /> or preferably 2-inch 

 bottom of concrete reinforced with poultry netting, and 

 with concrete sides. The benches may be supported by 

 iron pipe or concrete posts. (Figs. 21 and 22.) A com- 

 bination of slate, iron and concrete is often used in bench 

 construction. Sometimes water-tight concrete beds are 

 made, so that sub-irrigation can be practiced. 



Walks, alleys and roadways. Walks in commercial 



