6 MASS. EXPERIMENT STATION BULLETIN 317 



before they develop roots; therefore, the air above the bed must be kept moist 

 enough to prevent this succulent new growth from wilting. Humidity can be 

 maintained by using glass sash over the beds; but unless constant attention is 

 paid to ventilation, the propagating medium may become water-logged and the 

 cuttings die from lack of aeration. 



As soon as the cuttings have made a top growth and produced leaves, they 

 begin to manufacture food for themselves if they have light enough. Therefore, 

 the cuttings should be given all the light they will stand by removing the shades 

 on cloudy days. However, the shades must be put back on the propagating 

 beds immediately if the sun comes out, because even a few minutes of bright sun 

 on the cuttings often kills them. 



The only temperature control necessary is to keep the propagating beds from 

 becoming too hot. This is accomplished by shading and ventilation. 



The time to take blueberry cuttings is in the spring before growth starts. It 

 is a common practice to prune the bushes in late March and then cut from the 

 primings the wood suitable for propagating purposes. Great care is necessary 

 to prevent this material from drying out. 



The cuttings are made from wood of the previous season's growth and must 

 contain no fruit buds. Weak, spindling cuttings are not desirable because plants 

 grown from them are usually small, weak, and slow in growth. On the other 

 hand, cuttings over one-fourth inch in diameter seem to root less readily than 

 the smaller ones: but when they do root, they usually make larger, more vig- 

 orous plants. The best length is three to four inches, with the top cut made just 

 above a bud and the bottom cut just below and as close to a bud as it can be 

 made without injury to the bud. All cuts should be slanting and made with a 

 very sharp knife in order that they may be clean and smooth. 



The best propagating medium consists of a mixture of about 75 percent peat 

 and 25 percent sand. Because of the variation in American peats, unless one 

 known to be a good propagating medium can be obtained, it is better to use 

 German peat of the grade GPM. An ordinary cold frame makes a satisfactory 

 propagating frame if there is good drainage below it. About six inches of the 

 propagating medium is necessary and should be packed down well and leveled. 

 To prevent injury by root grubs, wire screen may be placed in the bottom of the 

 bed. German peat must be wet before use. This material is very difficult to 

 wet with cold water but can be wet easily with hot water. 



The best time to set the cuttings is about April 1 or before the buds begin to 

 break. It is best to start with the earliest varieties. They can be put in the 

 medium either at an angle of 45° or vertically, one inch apart, in rows two inches 

 apart. If each cutting is placed deeply enough in the medium so that only the 

 top bud remains above the surface, usually only this bud will develop and a 

 better plant will be formed. 



After the cuttings have been placed, the bed should be watered thoroughly 

 and the sash put in place. The shades can be left off until the buds begin to 

 break. This is desirable if the weather is cool. The shades may be made either 

 of burlap or slats supported about four inches above the sash. If the shades 

 are made of slats, the proportion of slats to space ought to be about three to one. 

 During the rooting period the cuttings must be watched closely. If any show 

 signs of rotting, the frames need to be ventilated by raising the sash slightly. 

 The shades are removed on cloudy days but must be replaced immediately if the 

 sun comes out. 



