TREATMENT OF THE YOUNG SEEDLINGS. 55 



in the new soil by means of a small dibble. These plants were half 

 to three- fourths of an inch high and had three to six true leaves. 



It is believed that a spacing of 2.5 inches in the flat is better than 

 2 inches, as the plants have a little more room and the 2.5-inch square 

 of earth is a very convenient size when the next transfer is made 

 into 4-inch pots. 



From this time on during the winter the plants were kept in a cool 

 greenhouse in which the night temperature was 55° to 60° F., and 

 which was given a large amount of ventilation. The day tempera- 

 ture reached ordinarily G5° to 70° F. It was found that a house 

 with a night temperature of 40" F. and a day temperature of (J0° F. 

 was too cold for such seedlings, as they made almost no growth at 

 all. In a warm house, 65° to 70° at night and 80° to 90° F. in the 

 da3^time, blueberries grow fairly well, but they are much subject to 

 injury by red spider {Tetranychiis hhnaculatus) , and their new- 

 growth while sufficiently extensive does not appear so robust as in the 

 60° to 70° F. house. 



For the first fcAv days the newly transplanted seedlings were shel- 

 tered from direct sunlight. Later, however, they were given all the 

 sunlight possible. It w-as found that during the winter, when well 

 established in a suitable soil and under proper moisture conditions, 

 the plants grew better when they received the fullest sunlight that 

 the greenhouse afforded. This statement applies to the plants in all 

 stages, whether in a seed bed or after the first transplanting or in 

 larger pots. 



In watering, the plants should be kept " on the dry side," as gar- 

 deners say. Water may advantageously be withheld until the surface 

 of the soil is dry, but this condition should not be allowed to extend 

 to a depth of more than about an eighth of an inch. Then a rather 

 thorough watering should be given, wdiich will carry moisture to the 

 bottom of the soil, but not run through. Such a watering at infre- 

 quent intervals is preferable to frequent light sprinklings that moisten 

 the surface only. Except for the brief period of percolation imme- 

 diately after w^atering, the movement of water in the soil should be a 

 capillary one, and from the bottom upward. Under such conditions, 

 if the soil is of proper texture, good aeration is insured. 



The shock of transplanting checks the growth of the seedlings for 

 several days. This checking of growth may manifest itself in one or 

 more of three ways: {a) The withering of the stem tip; {h) the 

 *' stagnation," or stoppage of expansion of the uppermost leaf rudi- 

 ment; and {(') the purpling of the older leaves. As these phenomena 

 when persistent have been much utilized in these experiments as 

 warnings of the existence of conditions antagonistic to growth and 

 as they may be of similar assistance to other experimenters, a de- 

 scription of them will be given. 



193 



