Plants as Affected by Insufficient Light. 143 



though of species that normally grow upright, are often 

 unable to stand erect without support. Familiar ex- 

 amples are cabbage and tomato plants that lop over when 

 planted out, because grown in the seed-box to transplant- 

 ing size without " pricking off" (106); and grain sown 

 too thickly on rich ground, that falls (lodges) before 

 maturity. 



239. Too Close Planting Causes Deficient Light and all 

 the resulting evils. Indian corn grown too thickly does 

 not ear well and is lacking in nutritive qualities; straw- 

 berry plants grown too closely do not fruit well and the 

 fruit lacks flavor and firmness; nursery trees grown too 

 closely are slender-stemmed, deficient in foliage and have 

 poorly -developed roots. A rule to govern distance in 

 planting has already been given (123). 



When a slender and flexible growth is desired, as in 

 trees grown for hoop poles, or willows for wicker-work 

 and tying, a certain amount of crowding is advisable. 



240. Weeds Cause Deficient Light in low-growing crops 

 as strawberries, dwarf beans, potatoes etc., and also tend 

 to rob the plants of food and moisture. They are, there- 

 fore, decidedly injurious (336). 



241. Plants Under Glass are Especially Liable to Suffer 

 from Deficient Light, because the walls and sash bars of 

 the structure necessarily intercept a considerable part of 

 the solar rays. The roofs of glass houses should be 

 formed of large lights of glass, with the smallest possible 

 sash bars, and the benches should be arranged to bring 

 the plants as near to the glass as possible. 



242. The Electric Light has been found useful as a sup- 

 plement to the scanty sunlight of short, early- winter 

 days, in forcing certain vegetables and flowers. 



