FORCING OF LETTUCE 209 



etc., will lollow. Airing should always be done by degrees, not admitting too 

 much at once. Growers should bear in mind that the temperature for an\- 

 plant should be changed gradually, both in the morning when increasing and 

 at night when reducing it. Air should never be admitted to the extent of lower- 

 ing the temperature suddenly. It is poor policy to allow the temperature to 

 rise more than five degrees over night before increasing the air. There should 

 be a steady rise with a steady increase of air. This suggestion, of course, refers 

 to the Winter temperature. In the early Fall and again in the Spring quite a 

 bit of air should be left on all the time. Good growers know the importance 

 of carefully regulating the ventilators. The inexperienced should study this 

 matter until they have mastered it, for the welfare of the plant depends largely 

 on it. At times airing seems like a nuisance, but it is one of those troublesome 

 things that we cannot afford to neglect. 



FEEDING 



It is not necessary to feed a Lettuce crop much if the soil in the bed is well 

 supplied with manure; but if the soil needs any assistance, this may be given 

 between crops, for it is not easy to feed a growing crop. Nitrate of soda, how- 

 ever, is good to give as the Lettuce is beginning to head, for it will increase the 

 size and hasten maturity. The most effective w^ay of using the soda is in water 

 in the proportion of a tablespoonful to three gallons. Give the plants a moderate 

 watering with this, keeping it off the foliage as much as possible. Do not use 

 the nitrate of soda when the soil is dry. It is better to give the bed a moderate 

 watering first, allow^ing this to settle, and then give the soda on the following 

 day. This applies where Lettuce is grown on a moderate scale, but where it 

 is grown in wholesale quantities, the soda may be sprinkled in between the 

 rows and then watered in; considerable labor will be saved in this way. But 

 in whichever way it is given, a moderate amount of soda is excellent. 



WATERING 



The ad\antage of solid beds becomes apparent in watering, for they do 

 not require water \-ery often, especiallj' after the crop is well established. When 

 water is needed give a thorough watering and then no more until necessarj-. A 

 thorough soaking when the plants begin to head will help to increase the size 

 and assist the heading. A good drenching at this stage is usually sufficient 

 to finish up the crop. No set rules can be laid down in this matter, however, as 

 much depends on the nature of the soil. Some soils take considerably more 

 water than others. As a general rule, when the soil gets dry, water must be 

 applied. 



DISEASES 



Lettuce is unfortunately subject more or less to disease. Much has been 

 written on this question and considerable advice gi\en. The Lettuce disease 

 has been called sunburn, but this term is misleading, as the disease spreads 



