TO INSURE A CROP OF HEAD LETTUCE 



115 



factory crop of head lettuce can be produced from open j^round 

 seeding in central latitudes. 



To insure a crop of head lettuce, except in cool regions, it is 

 necessary to start the plants under glass at least six weeks before 

 time for setting them in the open. Where open-air gardening 

 starts before April 1, lettuce plants usually may be transplanted 

 about April 15. Therefore the seed should be sown by the first 

 of March. It may be sown in flats in greenhouses or in the soil 

 of a hotbed. In either case the plants should be shifted in about 

 three weeks, or as soon as they are large enough to handle. They 

 may be planted in flats, about two inches apart each way (Fig. 

 64), or may be set in two and one-half inch pots. The latter 



Fig. 64. — Flats oi shifted letluce seedlings on greenhouse bench. 



method is preferable, for plants so handled are less sappy at the 

 time of the final transplanting, and their root systems are not 

 disturbed in the operation. However, good results can be secured 

 with plants from flats if all soil and weather conditions are favor- 

 able at the time of transplanting and care is taken to have plenty of 

 soil attached to the roots when the plants are taken from the flats. 

 Whether in flats or pots, the plants should be transferred in 

 the containers to a coldframe for hardening-off, at least ten days 

 before it is expected that they will be transplanted into the open 

 ground. Whether in the greenhouse, hotbed or coldframe, pots 

 containing lettuce plants should be plunged to the rim in soil or 



