The Bulletin. 25 



sash to retain moisture. Care should be taken to sow the seed thinly 

 so that the plants do not come up spindly from crowding. If the 

 plants are thick, they are much more liable to be affected with "damp 

 off" fungus. 



It takes, usually, from a month to six weeks in the fall to make a 

 plant of sufficient size for setting. The setting in the frames should 

 be done when the plants are small, just getting the fourth leaf. If 

 they are allowed to remain in the seed-bed until they get "necky," they 

 will not form good heads later. 



The plants are set in the frames 12 inches by 12 inches or 10 by 12 

 inches. After a bed is set, the cover should be drawn over to keep the 

 plants from wilting. In all bright, warm weather the covers should be 

 off so as to admit all the light and heat possible. 



The most important thing about the culture of lettuce is to have the 

 soil full of humus. It is practically impossible to raise good head lettuce 

 in a soil that is deficient in humus. It is also impracticable to try to 

 produce lettuce without commercial fertilizers. Manure is one of the 

 best means of supplying humus to lettuce beds, and there is, on most 

 soils, very little danger of applying too much of it. However, as manure 

 is usually scarce and high-priced, the cheapest method of adding most 

 of the humus for lettuce culture is by previous leguminous crops, nota- 

 bly coAvpeas. For small beds humus may often be conveniently supplied 

 in the form of street sweepings, swamp muck, or even peat or turf from 

 wild lands. The inorganic fertilizing elements can only be supplied 

 from the fertilizer Sack. Sufficient nitrogen is necessary to encourage 

 a rapid leaf growth. On the other hand, too much nitrogen will make 

 a soft, loose, leafy head that does not ship well. Phosphoric acid and 

 potash seem to make the heads firm and solid in texture. After several 

 years of experimenting on a sandy loam soil, I have found that two tons 

 per acre of the following fertilizer has given us the largest yield of good 



marketable heads : i i • a • i 



9 per cent Phosphoric Acid, 



5 per cent Nitrogen, 



7 per cent Potash. 



This formula is made up from the raw ingredients that are found to 

 be cheapest on the market. One half of this amount is applied broadcast 

 ten days before the plants are set, and the other half given as a side 

 dressing about February 1st. For fall and winter crops of lettuce in the 

 South, the Big Boston variety still holds the lead for shipping purposes. 



If lettuce is grown continuously on the same ground it will sooner or 

 later become infected with the diseases that are peculiar to this crop. 

 The most serious of these is the "drop" or "wilt" disease. This destroys 

 the plant just as it is getting ready to head. In our experiments against 

 this disease, spraying has proved impracticable. We have also found 

 that cutting and burying every diseased plant does not seem to lessen its 



