TEUCK FAKMING. 601 



proceeds sufficiently to congeal the particles of condensed water into 

 crystals of ice, we have white or h^jar frost, which cannot occur in this 

 latitude unless the thermometer falls as low as 4.4o. This deposition 

 of the vapor of water from the air is of vast importance to vegetation 

 wlien precipitated upon its foliage or imbibed by the hygroscopic 

 power of the well-tilled soil. If a screen is interposed between the shy 

 ami the surface of the earth the partial prevention of cooling of an 

 object near the ground is due to the reflection of heat by the lower sur- 

 face of the screen bacli to the object. The gardener avails himself of 

 this in various ways to screen his tender ])lants against injury from 

 iVost. ]Sone can occur on a cloudy night, because the clouds act as 

 si-reens and reflect back a portion of the heat they receive by radiation. 

 The nearer the clouds the greater the protection. Clouds of smoke may 

 be utilized upon the same principle. When a body is exposed on a 

 clear night its cooling will partially depend upon its contact with bod- 

 ies warmer than itself, from which it receives heat by conduction. 

 Bodies thus exposed will naturally radiate heat in a windj^ night as in 

 a calm one, but the motion of tlie warmer air, however slight, conveys 

 to them sufficient Iieat by conduction to prevent the deiiositiou of dew 

 or frost. 



In freeaing or anticipated freezing weather, the sash must be put on 

 long enough before sunset to warm the soil and confine a quantity of 

 heated air within the frames ; but even then the screen of glass will 

 often not be sufiBcient to protect even as hardy plants as cauliflower in 

 cold frames, particularly during clear, moon-lit nights. In such cases 

 an opaque covering for the glass, as board shutters, mats, or old carpet- 

 ing, will be necessary completely to protect against the effects of radia- 

 tion. At favorable locations to procure them the spreading leaves of 

 the large palmetto will be sufficient, or i)ine straw may be utilized. 



A certain degree of watchful care is necessary to the management of 

 plants under lass, for, be it understood, that is not only in the end the 

 best but the cheai)est material for covering hot-beds and cold frames. 

 [Should a substitute in any case be desired, common cotton cloth ren- 

 dered more translucent by means of the following ingredients may be 

 used : 1 quart pale linseed oil, 4 ounces rosin, 1 ounce sugar of lead. A 

 little of the oil and the sugar of lead should be ground together, then 

 the remainder of oil and the rosin melted together be added, and the 

 mixture applied warm with a wide brush]. To produce plants of a vig- 

 orous, healthy, stocky growth is the object aimed at. Too much light 

 and heat will produce a useless spindling growth ; too much moisture 

 and heat a luxuriant sappy growth, readily succumbing to cold, and 

 from too much moisture and deficient light the plants are apt to damp 

 off. It is necessary to study the effects of these agents upon plants in 

 hot-beds and cold frames, in order that the truck farmer may apph^ them 

 in harmonizing proportions towards the production of a sturdy vegeta- 

 tion. It must, however, be constantly borne in mind that retardation 

 rather than accelleration of growth is the object in view, and tlierefore 

 the glass should only be used for purposes of protection from cold and 

 too much rain. 



Plants should never be allowed to crowd each other under glass to 

 the injury of aU. As rarely any two kinds of vegetables reqmre the 

 same management, different species should not be planted in the same 

 frame or bed. 



Having secured a supijly of good plants, it is the best iDolicy of the 

 progressive farmer to transfer them to the open ground as early as the 

 season admits, but, after being transplanted, it will hardly ever pay the 



