NURSERY OPERATIONS. 31 



CARE OF SEED BEDS. 



During and after germination the surfaces of the beds are kept 

 quite constantly moist. Formerly new seed beds were sprinkled 

 once or twice each day, now all watering is done by flooding. The 

 beds are weeded early in the season, because if weeds attain large 

 size seedlings are almost certain to be damaged when the weeds are 

 pulled. In broadcasted beds only hand weeding is possible. When 

 seed was sown in drills it was possible to cultivate between the rows 

 and to some extent remove weeds with a narrow rake. 



The greatest danger to young seedlings is from the disease known 

 as "damping off/' which results from the attack of any one of several 

 fungi, which enter the seed as soon as the coat is cracked in germina- 

 tion. Many seedlings are killed before they push above the ground, 

 while all are subject to attack until several weeks old. The small 

 and comparatively weak seedlings of jack, Norway, and Scotch pine 

 are more susceptible to damping off than those of western yellow 

 pine. At Garden City, where damping off has been even more serious 

 than at Halsey, Austrian pine suffered more than any other species, 

 while Corsican pine was practically immune. This disease has been 

 the subject of a great deal of study, but it appears that at Halsey it 

 may best be controlled by treating the soil at the time of seed sowing 

 with a solution of sulphuric acid, consisting of three-fourths fluid 

 ounce of the acid in a gallon of water, applied at the rate of one 

 quart per square foot. All the soil, both below and above the seeds, 

 must be treated and the beds must be watered quite frequently until 

 germination is complete, in order that the solution may not become 

 concentrated. The treatment may injure some seedlings, but it 

 effectively prevents the disease, and the loss from the acid is incon- 

 sequental as compared with the loss from damping off. This acid 

 treatment is not recommended for a different soil, but all of the com- 

 mon preventives, such as dry and sterilized sand on the surface of 

 the beds, and sowing at various seasons, have failed entirely, so that, 

 if this treatment is effective elsewhere, it will greatly simplify the 

 nursery procedure. 



,The shade frames are kept over the seed beds during the entire first 

 year, and many seedlings which otherwise would die from overheating 

 or drought are saved. It seems probable that losses which were 

 formerly supposed to be due to damping off are nothing more than 

 the effects of drought. The shade frames make the moisture more 

 equable and at least reduce the frequency of watering. 



The size of seedlings at the end of the first season is shown in 

 Table 8. 



