454 



PITS AND FRAMES. 



the front upright lights, and by letting 

 down the top roof ones. Ventilation 

 through the front parapet, with correspond- 

 ing openings in the opaque part of the 

 roof at top, is also an improvement to be 

 recommended. 



Fig. 637 is a section of a pit for simi- 

 lar purposes, heated by a flow and return 



hot-water pipe, under the trellis on which 

 the plants in pots are to be set. The 

 back part of the roof is covered with 

 imbricated thick boarding, and in it ven- 

 tilators are placed. The front is glass 

 sashes, in a portable state — this being 

 necessary, as all operations connected 

 with the plants are carried on from with- 

 out. The trellis on which the plants 

 stand is of wood, and sufficiently open to 

 admit the heat to pass readily upwards. 



Fig. 638 is a strawberry house or pit, 

 heated by hot water — the shelves for the 



pots being suspended from the rafters by 

 wire brackets, hooked on so that they can 

 be entirely removed. The operations of 

 culture are chiefly carried on within, 

 which is a great advantage over the last 

 example ; as is also the angle of elevation 

 being higher, and better adapted to the 

 season when strawberry forcing is carried 

 on. During summer this pit may be 

 advantageously used for ripening tomatos, 

 Chilies, cucumbers, and melons, in pots, 



&c. The ventilation is not shown in the 

 section. It may, however, be understood 

 as being effected through the front parapet 

 and top of the back wall. 



Asparagus pits. — In the royal gardens 

 at Frogmore, asparagus is cultivated dur- 

 ing winter in pits constructed as in the 

 annexed wood-cut, fig. 639. This, al- 



Fig. 639. 



though not exactly a new system, has 

 merits deserving of imitation, and may 

 be much improved by a very slight alter- 

 ation. In the royal gardens, permanent 

 beds are formed within pigeon-holed 

 side walls. Between the pits are placed 

 hot-water pipes, in an open chamber, 

 covered with thick boarding to walk 

 upon and keep down the heat. The heat 

 is thrown into the atmosphere of the pits 

 through the openings in the brick-work, 

 and slightly into the bed by the same 

 means. The pits are covered with a 

 ridged roofing of boards, which are 

 opened in mild weather to give colour to 

 the grass, and are removed when the crop 

 is being cut. Sea-kale roots are taken 

 from the quarters and planted close by 

 the sides of the pits a without, where no 

 hot-water pipes are. 



Improved asparagus- pit. — We do not 

 think the Frogmore pits by any means 

 the best calculated for the end in view, as 

 the heat applied must be both ineffective 

 and attended with considerable waste. 

 We would suggest, as an improvement on 

 these, chambering the bottoms of the pits, 

 and placing hot-water pipes in them, 

 resting on piers of bricks 12 inches high, 

 laying the floor of the chamber over the 

 depth of 9 inches with charred sawdust, 

 as a non-conductor of heat, to prevent 

 its waste by absorption in the soil beneath. 

 To prevent the loss of heat by the side 

 walls of the chamber, we would also cut 

 off conduction by building the walls, 

 which support the pavement on which 

 the soil beds are formed, 6 inches distant 

 from the side walls of the pit. Earthen- 

 ware or metallic pipes should be set ver- 



