LETTUCE. 251 



method is little used, however (Fig. 33, page 99). 



The character of the soil has very much to do with 

 the ease of growing lettuce, and also with the quality of 

 the crop. Good lettuce soils should be very open and 

 porous (made so by the presence of sand and the absence 

 of clay), with a capacity to hold much water, but an 

 ability, nevertheless, to remain comparatively dry on top 

 (page 96). 



The electric light has a marked effect in hastening the 

 maturity of lettuce (pages 80, 101). 



A lettuce crop matures in seven to ten weeks if the 

 seed is sown in September. In the winter months, two 

 to four weeks longer may be required (page 101). 



The first sowing (in early September) may be made in 

 the open, but subsequent ones are made in flats or in 

 vacant places in the beds (or possibly in hotbeds). Best 

 results are obtained if the plants are transplanted twice, 

 once into other flats or into temporary beds (about 4 

 inches apart each way), and again into their permanent 

 quarters, where they should stand about 8 inches apart 

 each way (pages 101, 102). 



Leading varieties are the Boston Market (or White- 

 seeded Tennis Ball) and Grand Rapids. The former is a 

 heading lettuce (Fig. 34), and the latter non-heading (Fig. 

 32). There are several other good varieties (page 104). 



Aphis or green-fly is held in check by keeping the 

 plants in a uniform condition of vigorous and healthy 

 growth, and then by fumigating with tobacco or by strew- 

 ing tobacco stems amongst the plants (page 104). 



The rot is worst in soils which remain wet on top and 

 which contain much manure or decaying matter. Keep- 

 ing the temperature high and the house very wet also 

 favors it (page 105, Fig. 35). 



The mildew is worst in houses which are kept very 

 close and warm and wet. It is most frequent when 

 draughts are allowed to strike the plants. When it ap- 

 pears, evaporate sulphur (first, however improving the 



