64 ALPINE PLANTS 
bad weather. Sidelights are also made to open, and should 
be opened when the weather is at all warm, the object of 
the alpine house being not to force the plants by artificial 
heat, but mainly to keep the foliage and blossoms clean, 
and to enable everything to be seen and attended to in 
comfort even in the roughest of weather. 
Although, as has been shown, a house of the style of the 
illustration may be deemed ideal for the purpose, still it is 
by no means essential that it should conform in detail to 
that plan, the only urgent necessities being adequate means 
of ventilation, and plenty of light. 
Whether we have a greenhouse or frames only the 
principles of cultivation of alpines in pots and pans will be 
the same. Pans differ from ordinary flower-pots only in 
shape, a pan having a greater surface area and less depth, 
whereas a pot is deeper than it is broad. Plants that are 
of close, compact, tufted or shrubby growth are more 
suitable for growing in pots, whilst prostrate growers, and 
such as root into the soil as they grow, will naturally thrive 
better when afforded the greater surface of the pan. Quite 
a number of trailing plants, such as Saponaria ocymoides, 
the acenas, Arenaria montana, Nepeta glechoma variegata, 
etc., make a very effective display when grown in pan 
pyramids constructed by setting a small pan or a pot inside 
a large one, and filling the intervening space between the 
sides of the smaller and larger with soil. By planting young 
pieces all around the whole quickly becomes furnished, 
making a conical mound of beautiful growth and bloom. 
The interior of all pots and pans must be perfectly clean, 
otherwise healthy growth will not be maintained. 
