242 VEGETABLE FORCING 
copiously with a hose, care being taken not to wet the 
heads or the foliage, and special fertilization may also be 
given at this period. Previous to the formation of heads 
there is no objection to applying water as a spray. 
A moist atmosphere at all times is favorable to the 
growth of cauliflower. In warm, sunny weather it is of 
advantage to sprinkle the walks with water in order to 
increase the humidity in the house. 
Temperature.— While cauliflower is often grown under 
glass with lettuce and radishes, it thrives best at some- 
what higher temperatures than are required for these 
crops. The temperature at night may be 50 to 55 degrees, 
and by day 65 to 70 degrees, though good crops are often 
grown with less heat. 
Ventilation Ventilation is essential to the growth of 
healthy plants and to the formation of good heads, but 
cauliflower is very sensitive to cold drafts, which may 
cause the leaves to droop and prevent head formation. 
Some fresh air should be admitted to the houses daily, 
but cold drafts should never strike the plants. 
Cultivating.—The beds of cauliflower should be cul- 
tivated at frequent intervals. This is of special value in 
conserving soil moisture and in encouraging the most 
satisfactory growth. One of the chief objections to inter- 
crops of lettuce or radishes is that they interfere to some 
extent with thorough cultivation. 
Insect enemies.—The green aphis is the most serious 
pest of cauliflower grown under glass, but it is easily 
controlled by tobacco fumigation. (See page 105.) The 
larve of the cabbage butterfly sometimes feed on plants 
started during the fall months. Arsenate of lead, or, if 
preferred, fresh pyrethrum or insect powder, may be used 
to poison this pest. 
Diseases.—Cauliflower is subject to the same diseases 
as cabbage and other brassice. ‘The commonest are 
soft rot or stem rot, black rot and club root. They sel- 
