18 MASS. EXPERIMENT STATION BULLETIN 318 



The commercially grown sets started more readily, and the large size, % to 

 1 inch, was ahead of the smaller size, }^ to % inch, all season so far as top growth 

 was concerned. The greatest difference observed, however, was in the number 

 of seed stalks and multiple bulbs produced, which was determined by actual count 

 during the latter part of the growing season. The percentages of seed stalks and 

 multiple bulbs are given in Table 7, for the two-year average. The 1932 sets 

 showed much greater differences between fertilizer treatments regarding the 

 development of seed stalks and multiple bulbs than did the 1933 sets. This can 

 be explained by the fact that in 1933 care was taken to select for planting sets 

 having an equal weight, but the 1932 sets were taken at random and would there- 

 fore in some cases have a larger number of the sets near the upper or lower limit 

 of size. Table 7 shows that neither seed stalks nor multiple bulbs were an im- 

 portant factor with well-grown sets under ^ inch, but when larger sets were used 

 they may become so numerous as to seriously reduce the value of the crop, for a 

 set which develops a seed stalk or divides will never become a first grade onion. 



Table 7 gives also the yields per acre of several different grades of onions 

 produced. The bulbs over \\^ inches and without seed stalks or divisions rep- 

 resent all of the first grade marketable bulbs and are a good basis upon which 

 to judge the relative merits of the differently grown sets. The yields in this grade 

 from the small sets showed no appreciable difference between the fertilizer treat- 

 ments, and in only one case with the large size was the yield of first grade bulbs 

 reduced much below that of the small size. In other cases the large sets gave 

 approximately the same yields of first grade onions as the small size and in addi- 

 tion several hundred pounds of second grade onions. The commercially grown sets 

 did not do quite as well as the Station-grown sets. 



Table 7. A two-year comparison of onions grown from commercial 



SETS AND FROM SETS PRODUCED UNDER EXPERIMENTAL CONDITIONS. 



2-Year Average Yields, Pounds per Acre 



Fertilizer Percentage Percentage Bulbs without Seed 



Treatment per Having Having Stalks Bulbs 



Acre under Which Multiple Seed Multiple Having Total 



Sets Were Grown Bulbs Stalks Over Under Bulbs Seed 



1)4, inches \ x /i inches Stalks 



Sets Vi to % inch in Size 



500 lbs. 0-12-8 0.19 1.21 40,938 105 4S 478 41.509 



500 lbs. 2-12-8 1.0S 39,312 153 420 39,885 



500 lbs. 4-12-8 0.36 1.34 39.886 105 114 478 40,583 



1000 lbs. 4-12-8 55 0.82 39,934 19 239 335 40,528 



Commercial 0.91 2.74 30,969 230 411 813 38,423 



Sets % to 1 inch in Size 



500 lbs. 0-12-8 2.56 17.86 39.9S1 57 976 6,963 47,978 



500 lbs. 2-12-8 2 73 17 45 10,268 13V 995 6,647 48,045 



500 lbs. 4-12-8 1.84 18.69 39.312 07 708 7,011 47.098 



1000 lbs. 4-12-8 6.18 24.70 38,260 9 1,894 8,350 48.513 



Commercial 11 11 25.81 30.150 287 1,180 9,153 49,770 



In 1934 an attempt was made to learn to what extent the size of sets could be 

 controlled by pulling them when they had made sufficient growth rather than 

 allowing them to grow till more mature, and also to observe the influence of this 

 early pulling on keeping quality and performance when planted for bulb produc- 

 tion. Later plantings of seed were also made to see how they compared with the 

 more common practice of early planting. It was found that by planting heavily 





