256 ON TAKING IN GREENHOUSE PLANTS. 



shut, and warm ; this occasions a most pernicious damp to exhale 

 from every part of the house, and even from the earth in the pots ; 

 which fixes on the leaves, and other parts of the plants, to their 

 inevitable injury, particularly the younger parts, such as were the 

 produce of the preceding summer. If this kind of weather continues 

 for any considerable time, it will be adviseable to give a little fire heat, 

 to help in drying up these baneful exhalations, and also as inucb air, 

 as can be safely admitted by the doors, and front windows ; more 

 especially when fire is added ; otherwise the heat of the flues will, 

 instead of expelling the contaminated air, rather occasion it to exhale 

 more freely, and be of worse consequences. 



At this season also, the plants should be regularly examined to 

 clear them of all dirt, and also to scrape oft" any moss, &c. that may 

 have grown on the surface of the mould, and to renew it with a little 

 fresh loam. This contributes much to their good appearance, if 

 neatly executed. 



Very little fire heat seems to be requisite to the preservation of 

 greenhouse plants, in this climate; in fact, the less it is found neces- 

 sary to use, the better. I have never practised it, (except in the case 

 of damps, as before mentioned,) until I perceived the frost so severe, 

 as to lower the spirit in the thermometer several degrees below the 

 temperate point, and then merely sufficient to raise it again to the 

 above mentioned point. If this can be done without the assistance of 

 fire, so much the better, for which purpose, bass mats must be 

 used along the lower parts of the house, where they can be con- 

 veniently fastened ; these will be of infinite service even when fire is 

 used, as less of that element will suffice ; but they should be always 

 taken off in the day to admit the light, unless the weather happens to 

 be particularly severe. 



Sometimes in the depth of winter, there is a succession of very 

 clear weather for several days together, wherein warm sunny days, 

 succeed the coldest frost, and nights in which fires have been abso- 

 lutely necessary ; in this case, it will be requisite to give all the air 

 possible in the day, (unless strong harsh winds, or other occasional 

 preventatives happen to prevail,) observing, to shut the windows up 

 close, earlv in the afternoon, so as to include part of the natural heat 

 of the atmosphere, within the house. Such weather renders an in- 

 crease of water necessary, especially over the entrance of the flues, 

 where the fires have the greatest force. It should be administered 

 in the morning", and ought to be kept in the house all night to expel 

 any frosty particles it may have imbibed, and render it nearly equal 

 to the temperature of the air of the house. 



