MARKETING LETTUCE 
varieties do not succeed under glass, or where a specialized market 
has been developed for this particular type of lettuce. 
HARVESTING 
The usual method of harvesting the crop is to go over the field 
two or three, or in rare cases even four times, cutting only the 
merchantable heads each time. Generally the crop matures rapidly 
enough so that these cuttings may be made at intervals of one to 
three days, or a week at the most. Sometimes a crop matures so 
uniformly that one cutting suffices. 
Heads which are in condition to harvest usually can be detected by 
their firmness and color, provided growing conditions have been 
favorable. As the plant matures it takes on a somewhat lighter ap- 
pearance at the center, because of the exposure of the blanched 
Fig. 4. — White Paris Cos lettuce, or Romaine 
leaves which form the head. In some cases mature heads show a 
slight brownish-purple or pinkish discoloration on the tips of the 
uppermost encasing leaves. As a rule, well-matured heads show a 
compact and solid formation in the center distinct from the outer 
whorl of loose leaves. Under unfavorable conditions, however, head 
lettuce often becomes mature without being firm. 
The firm head of good quality should not be confused with one 
that is slightly past maturity and has begun to develop a hard seed 
stalk in the center of the head. Such lettuce is bitter and coarse, of 
very poor quality, and usually is unmerchantable at any price. Im- 
mature heads when cut wilt rapidly, and are loosely formed and 
spongy instead of firm ; overmature heads generally show a deep dis- 
coloration and a pithy or woody condition of the stem end when cut. 
Whenever high prices prevail early in the season growers are 
tempted to begin harvesting and shipping too early, before the crop 
has reached the proper stage of maturity. Little, if anything, is 
