CONSTRUCTION OF IIOTBEDS 
III 
lined with boards, as previously described (156). Port- 
able frames are placed on top of the manure, which is 
about even with the surface of the ground, and the 
frames are then banked with manure. This plan requires 
more manure, although the beds furnish heat for a longer 
period, and they settle with the manure, and so the plants 
are always the same distance from the glass. Another 
plan often used southward and on poorly drained land 
is to place the manure on top of the ground, and in this 
way dispense with the pit. This requires more manure 
than either of the plans described, because there is no 
protection at sides and ends. Liberal space must be 
FIG. 20. FLUE-HEATED FRAME 
provided for banking the frame when it is placed so high 
above ground. Manure’ greenhouses are sometimes used 
by placing hot manure under the benches; a central 
alley is provided, so it is possible to work in the house 
with the same convenience as in houses heated by flues, 
steam or hot water. The plan is not recommended, be- 
cause steam o r hot water heating is more economical 
and much more satisfactory. 
The manure from spent hotbeds has lost most of the 
nitrogen, but it is useful for composting and fertilizing 
crops which do not require large amounts of this ele- 
ment. It is also useful for placing in the bottom of flats 
Aefore transplanting. 
