68 EXPEKIME]SITS IN BLUEBKRRY CULTURE. 



period between 10 and 8 o'clock, and after September 12 the shades 

 were left off altogether. 



The plants were watered with a swift spray from a hose, the water 

 being applied only when necessary to keep the soil from actually 

 drying out. The sand between the pots w^as seldom allowed to become 

 dry to the depth of more than half an inch. A sand mulch of about 

 a quarter of an inch on the top of the soil in the pot was found useful 

 in preventing the rapid drying of the soil by direct evajioration. 



(29) By the use of the cultural methods already described, seedlings ok 

 the swamp blueberry have been grown into robust plants of a maxi- 

 mum height of twenty-seven inches at twelve months from germina- 

 TION. 



The grow^th of the plants out of doors during the summer was 

 remarkably vigorous. Hitherto experimenters with seedling blue- 

 berries have been able to produce only comparatively small plants at 

 the end of the first season, as shown by the following citation from a 

 publication of the best-known experimenter:" 



The blueberry makes much less growth the first two years from seed than 

 the huckleberry, but grows faster afterward. The third year I have had them 

 make a growth of G to 8 inches. The low blueberry and huckleberry begin to 

 bear at 3 or 4 years, while the high-bush blueberry requires 4 to 6 years. 

 P'rohi 1 to .3 inches growth the first year is about all you can expect. 



Under the system of treatment described in the present bulletin 

 seedlings have been grown to a height of 27 inches at twelve months 

 from germination. Out of the seedlings of 1908, 250 w^ere carried 

 through to the close of the season of 1909 in (i-inch pots. Of these. 15 

 were stunted plants. The remaining 235 had an average height at 

 the end of the season of exactly IS inches. The larger stems were 

 often a quarter of an inch in thickness, and the main trunk, half sub- 

 merged in the ground, sometimes reached a diameter of half an inch. 

 The general appearance of these plants is shown in Plate VIII. 



The principal features of cultural treatment which have contributed 

 to this development are {a) the autumn germination of the seeds, 

 {h) the use of suitable acid soils, (c) the plunging of the pots, and 

 {d) the partial shading of the plants during the heat of summer, the 

 application of these cultural methods having been guided throughout 

 by the discovery of the existence of a mycorrhizal fungus in these 

 plants and its treatment as essential to their nutrition. The system 

 of germination and the character of the soils used have already been 

 described in detail. The exact effects of the plunging and the shading 

 remain to be considered. 



It has already been shown (p. (MS) that when a j)lant is not 

 plunged, the minute rootlets that lie against the sides of the pot 



a Dawson. .Tncksnu. ruitixator and Country Gentleman, vol. .50, 1.S85, p. 660. 



