226 



THE GREEN-HOUSE. 



that planting in earth for a few weeks such bulbs as 

 are to be blown on water, is the best mode of causing 

 them to protrude roots freely, which when they are 

 placed on water at once is not always the case. 

 Whenever the roots are a quarter of an inch in length, 

 take them out of the earth, wash them gently so as not 

 to injure the radicles, and then place them on the water. 



It is not essential that bulbs on water should be 

 placed in much heat, for the principal stimulus to a 

 new-planted bulb is the moisture ; and if the room in 

 which the glasses are placed be kept to 45° or 48°, 

 that will promote their vegetation for some time as 

 much as 10° or 15° higher. When the flower-stem 

 has risen an inch or two, then the heat may be con- 

 siderably increased : that is, the glasses may be moved 

 from a room without a fire to one where a fire is kept, 

 and where the temperature will generally be found 

 between 55° and 65°. Here they will advance with 

 considerable rapidity, especially if placed on a stand 

 or stage near a window of south or south-east aspect. 

 They will blow however without any sun ; but the 

 colours of the flowers will be inferior. It is a re- 

 markable circumstance of the crocus, that it keeps 

 its petals expanded during a tolerably bright candle 

 or lamp light, in the same way as it does during the 

 light of the sun. If the candle be removed, the cro- 

 cuses close their petals, as they do in the garden when 

 a cloud obscures the sun ; and when the artificial light 

 is restored, they open again as they do with the return 

 of the direct solar rays. 



