Book II. CULTURE OP BOTANIC HOT-HOUSES. 827 



either the lights should be leaded, or the laps stopped with putty, so that a sufficient 

 quantity of air may be always given, and the house kept to a more regular heat. "When 

 the laps of the glass are left open, a great deal of air is admitted, which is often injurious, 

 particularly on a cold windy night. The thermometer should never be allowed to be 

 below 60 of Fahrenheit's scale ; if it gets above 70 on a fine day, a little air may be 

 given, which should be taken away early, and the house shut up warm ; it then requires 

 less fire to keep up the heat through the night. If the house is heated in the common 

 way by flues, and the plants are plunged in tan, care must be taken not to give these 

 too much bottom heat, as it will injure their roots, or too much water in winter, as it is 

 apt to rot them. Particular caution is necessary for watering in winter, not to wet the 

 tan, as it makes the worms very troublesome ; they often destroy young plants by 

 throwing the mould out of the pots ; but a better way is the one now very generally 

 adopted, viz. to do without plunging in tan. Some hot dung or tan may be still kept 

 in the pit to throw up a little warmth, on which should be put a good thickness of sand 

 or gravel for the pots to stand on, and the plants will thrive much better than when 

 plunged in tan : it is also coming nearer to nature, which should be always studied in 

 the cultivation of plants, both in soil and situation. In tropical countries it is the sun 

 that heats the earth in which the plants grow, not the earth that heats the air; and 

 the heat must be kept up in the stoves accordingly. If the houses are heated by steam, 

 no tan is required. The plants may be set on stages, or any way that is most conve- 

 nient. Some of them may be planted out in the house, where they will grow in greater 

 perfection, and flower and ripen fruit better than when confined in pots. 



6215. To have plants look well they should be always kept clean and free from insects : if infested with 

 any species of aphis, the house should be smoked with tobacco, which instantly destroys them. The red 

 spiders are likewise a great pest to cultivators, but are also easily destroyed. One pound of sulphur vivum, 

 nixed up in a pail of quick-lime, and the flues brushed all over with it as a common whitewash, will de- 

 si i >y any quantity of them, and make the house look light and clean. The mealy bug is also troublesome if 

 left to increase on the plants ; but as soon as they appear they should be brushed off as well as the scaly in- 

 sects ; for, if left to increase, they will disfigure the plants, and be very difficult to get rid of. In fine 

 weather the plants should be often sprinkled over with water from an engine, and the house shut up warm 

 afterwards, which is a great means of keeping them clean and making them grow luxuriantly. Air 

 should be given in the morning as early as possible, in fine weather, as it sweetens the house, and makes 

 the plants healthy. It should also be taken away early in the afternoon, and the house shut up warm, that 

 they may not be chilled by the night air. 



6216. In potting plants, care should be taken to drain the pots well with broken potsherds or rough bits 

 of turf ; for nothing injures them more than letting them get sodden with too much wet. The best time 

 to shift them in fresh pots is the spring, but some will require to be shifted again in autumn, to have them 

 thrive well. The free-growing kinds cannot be well overpotted if there be plenty of room for them in the 

 houses : they will thrive and flower better for being in large pots. Others that are more tender should 

 be kept in as small pots as possible, that they may not get sodden, and lose their roots. (Bot. Culti- 

 vator, 1.) 



6217. The resent hot-houses of the ornamental garden may be divided into those for 

 forcing hardy flowering plants and shrubs, and those for propagating exotics by seeds, 

 cuttings, or otherwise. 



6218. Herbaceous plants and flowering shrubs are generally forced in pits or low houses; and as soon as 

 the flower-buds begin to expand, removed to the green-house or drawing-room, there to prolong the flower- 

 jng season. The shrubs should be previously established in the pots, by being planted and plunged in 

 the open reserve-garden a year beforehand : the autumn before forcing they should be thrown early into 

 a state of rest, by covering them with canvass frames to exclude rain and sun, but so as to admit cold and 

 air. This operation should be commenced in July ; and the first course of pots may be removed to the pit 

 in November or earlier. Herbaceous plants of most sorts, especially of the fibrous-rooted kinds, may be 

 taken up with balls, and planted in pots early in the autumn preceding the winter in which they are to be 

 forced. Fusiform-rooted sorts earlier, as they do not rise so easily with balls ; and the bulbous sorts, the 

 bulbs being out of ground, may be planted in the end of autumn, plunged in the open ground, and covered 

 with rotten tan or ashes, and taken up as wanted. It is of some consequence to remark, that the flowers 

 should be pinched off both the shrubs and herbaceous plants, the summer preceding the forcing season, 

 in order to communicate additional strength, and aid in throwing them more early into a state of rest 

 The bottom heat may either be from tan or dung, or a vault heated by flues or steam ; but the former we 

 consider as most to be depended on. The temperature of the air of the house may at first setting in the 

 plants be kept at 50 or 55 ; and in a fortnight, raised 10 degrees higher. After that, it may be kept up 

 to 65 or higher, admitting air during sunshine. The temperature of the pit should be kept as high as 

 that of the air. Successional supplies should be kept for the first fortnight in a cooler house, or in the 

 coolest part of the pit; or the temperature, on their admission, may be somewhat lowered. The other 

 points of routine culture need not be entered into. 



6219. The propagation-house requires to be kept at a much more moderate tempera- 

 ture both as to the atmosphere and the bottom heat than the forcing-pit or the principal 

 stove. It need seldom exceed 60 in winter, and 65 in summer. Abundance of air 

 must be given at certain seasons when damp and mouldiness begin to appear ; and 

 shading and watering, so as to produce a moist atmosphere, must be attended to in the 

 summer season. 



