No. 7. DEPARTMENT OF AGRICULTURE. 601 



or less confined, the soil being shallow in the flats, and thus over- 

 growTi plants are less frequent with flat grown than with bench 

 grown plants. If it wpre possible to set the plants every time just 

 as soon as they were large enough this advantage would be slight 

 but it is frequently necessary to hold them several days after they 

 are of sufficient size and the flat grown plants can be held with less 

 danger of injury than those grown in beds. The Toledo growers 

 do not let their plants groAv as large as the Ashtabula growers be- 

 fore setting in the permanent beds. 



In our own houses we start the lettuce in flats and make one 

 transplanting into flats. The first crop is not transplanted but once 

 until it is transplanted from the flats to the beds. For the second 

 and third crops the seed is sown in flats, the seedlings pricked out in 

 flats and as soon as crowding begins the plants are transplanted into 

 two-inch pots or into flats and given more room. When the pots 

 are used they are plunged into the soil between the rows of lettuce, 

 twice as many pots as there are plants in a row. In this way we 

 are able to secure very stocky plants which when planted by the side 

 of those which have not been transplanted the second time show a 

 gain of two or three weeks over the smaller plants. This gain in 

 time we think justifies the extra work involved. By setting the pots 

 between the plants in the beds we have two crops growing on the 

 same ground at one time and thus economize room. When the 

 plants are plunged in the sub-irrigated beds we give the soil a thor- 

 ough watering as soon as the pots are in place and little or no further 

 watering is needed as a sufficient amount of moisture is drawn into 

 the pots from below. The same is true of the beds watered with 

 the Skinner system. I would not recommend this practice, how- 

 ever, where the watering is done with a hose in the old fashioned 

 way. 



When the plants are set in the permanent beds they are spaced 

 7 by 7 inches which we think a very satisfactory distance. The soil 

 between the plants is stirred once or twice with hand weeders. This 

 is done to kill weeds and to i>revent the formation of a crust on 

 the surface of the soil. If the green aphis is troublesome we scat- 

 ter tobacco dust over the surface of the soil just before the leaves 

 spread enough to cover the ground. Much care is taken in distribut- 

 ing it not to get the dust on the lettuce leaves as it is very hard 

 to wash off after it has been on the leaves for some time. It is 

 also a good plan to work some of the dust into the surface of the 

 soil before planting. 



Most growers aim to keep a night temperature of 4.5 degrees with 

 a day temperature at least 10 degrees higher. We aim to run the 

 temperature somewhat higher than this at night, 48 to 50 being 

 what I consider about right. On cloudy days we do not try to run 

 the temperature above GO and 55 degrees is satisfactory. When 

 the sun shines the temperature often runs very much above this 

 but no harm will result if the ventilators are opened wide. Ven- 

 tilating the houses is one of the most important operations connected 

 with greenhouse work and I might add that it is the one most com- 

 monly neglected. Our houses are provided with ventilators on both 

 sides of the ridge and on the sidas and we make use of all of them. 

 It is only on very cold, zero or below, weather or snowy days that 



