The Bulletin. 11 



FERTILIZERS. 



As has been said before, humus or organic matter is the basis of 

 successful lettuce culture. Any or all of the available sources of 

 organic matter, such as manure, compost, muck, peat or cover crops, 

 should be used to make lettuce soils rich in humus. The additional 

 ingredients necessary can be most cheaply supplied from the com- 

 mercial fertilizer sack. Sufficient nitrogen is necessary to encourage 

 a rapid leaf growth. An excess of nitrogen will make a soft, loose 

 head that does not ship well. Phosphoric acid and potash seem to 

 add the firmness to the heads necessary to make them carry well to 

 market. A good formula for lettuce is : 



4 per cent nitrogen, ^ 



7 per cent phosphoric acid, V 1,500 to 2,000 pounds per acre. 



8 per cent potash, J 



This formula might appear to be low in nitrogen. It is found 

 cheapest, however, to apply nitrogen by the use of a leguminous crop 

 growing on the land during the summer. As nitrogen is the fer- 

 tilizing constituent most readily lost from the soil, it should not be 

 applied in large quantities till the crop is in a sufficiently growing 

 condition to quickly take it up. For this reason, and also that the 

 previous cover crop of cowpeas has added considerable nitrogen, this 

 most expensive fertilizing constituent in the formula is reduced. 

 After the crop is in vigorous growing condition, 100 to 150 pounds 

 of nitrate of soda may be applied as a top dressing and raked in be- 

 tween the plants. 



With the proper use of summer leguminous crops, 1,500 to 2,000 

 pounds of the above mixture will be found sufficient. Half of this 

 should be sown broadcast on the land and harrowed in a week or two 

 before the plants are set. The other half should be raked in between 

 the plants three to four weeks after setting. 



Most truckers find it cheapest to buy the raw fertilizing materials 

 that ofler best on the market, and to make their own mixtures accord- 

 ing to percentage desired, rather than to buy ready-made fertilizers. 



HARVESTING. 



Lettuce should be cut and packed only when dry. The plants are 

 cut close to the ground and the outer leaves removed. Though all 

 the plants in a bed may be planted the same day, it will be found 

 that there is a great deal of difference in the time of their heading. 

 In cutting it will be found necessary to go over the beds several times. 

 Lettuce should be carefully graded. This is easily done by selecting 

 and cutting at one shipment only those heads that are firm and up to 

 size. A day or two later the same bed will give another crop of just 



