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; (8) 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 1% 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 
