138 



PRINCIPLES OF PLANT CULTURE 



screens of lath (Figs. 61, 62), cloth or brush (Fig. 63) 

 are often placed over beds containing cuttings or tender 

 seedlings, as of many cone-bearing trees. Cuttings in 

 the nursery may be shaded by supporting a board over 

 the row, on short stakes (Fig. 64), so as to protect them 



during the warmer hours 

 of the day. Shingles, 

 flower-pots or large green 

 leaves, as of the burdock, 

 are useful for shading 

 plants of the cabbage, 

 tomato and the like. 



In culture under glass, 

 the glass is often thinly 

 washed with lime or clay to render it partially opaque, or 

 lath screens are used either above or below the glass. On 

 greenhouse benches, sheets of thin paper or light cloth 

 screens are useful for shading cuttings, recently-planted 

 seedlings and germinating seeds. 



-V'v^ 



FIG. 62. Shed screen built of three- 

 inch-wide slats, for shading tender 

 plants and for storing pots and boxes 

 of slow-germinating seeds. 



FIG. 63. Brush screen, for shading tender plants in the open ground. 



Shading should never be so put on as to prevent a free 

 circulation of air about the plants. 



A shade that obstructs only a part of the rays of sun- 

 light at a time, as does the lath or brush screen, is gen- 

 erally preferable to one that continuously breaks the 

 force of all the rays, as does paper or whitewashed glass. 



