THE CULTURE OF SET ONIONS 13 



Time of Harvest 



Growers have long felt that onions harvested during early maturity kept much 

 better in storage than onions which had fully matured. Data from trials con- 

 ducted in 1939 show that early harvesting does result in better keeping quality 

 but at the expense of maximum yields. 



Table 8. — Influence of Time of Harvest on Yield and 

 Keeping Quality of Set Onions. 



Harvested when 50 per- Harvested 10 days later 



cent of tops were "down" when all tops were "down" 



Yield 50 lb. Percentage Loss Yield 50 lb. Percentage Loss 

 Bags per A. by Oct. 20 Bags per A. by Oct. 20 



Locally Grown Jap Sets 610 8.4 735 14.0 



Imported Globe Sets 445 12.5 570 18.0 



Imported Jap Sets 455 15.6 540 22.0 



The earl}' harvested onions had an average loss of 12.3 percent by October 20, 

 while fully matured onions had an average loss of 18 percent. However, the 

 fully matured onions yielded 20 percent more at harvest time, which in this 

 instance more than offset greater losses in storage. 



The results of this experiment supply further evidence that much of the disease 

 infection takes place in the field late in the season. As the plants mature, the 

 tops break over and the outer bulb skins loosen up. Greater opportunity is 

 thereby afforded for the entrance of disease organisms, so that the longer the 

 crop remains in the ground the greater will be the number of infected bulbs. 

 The rank growth of weeds which usually takes place soon after the tops begin 

 to go down is another contributing factor. Excess moisture from rains and heavy 

 dews does not e\'aporate rapidly and conditions are favorable for disease infection. 



Methods of Harvesting and Curing 



The most common method of harvesting onions in the Connecticut Valley has 

 been to pull the bulbs, rake them into windrows and clip off the tops. This may 

 take from a few days to one or two weeks. Finally the clipped onions are put 

 into used burlap bags and left standing in the field, where they may remain for 

 several weeks more before the}- are screened and either marketed directly or 

 placed in storage. It often happens that when the bags of onions are left in the 

 field and on the ground the burlap bags rot out completely where they come in 

 contact with the ground and it becomes necessary to turn them end for end. 



All available evidence shows that once the necks of mature bulbs are fully 

 cured and dry, the}' are not easih- infected. The critical period begins with 

 approaching maturity and continues until the necks have completely dried down. 

 As long as the bulbs are in contact with the ground during this ripening and 

 curing period, infection can take place readily. It is obvious, therefore, that 

 weather conditions during harvesting and curing can have an important bearing 

 on the keeping quality of onions in storage. If dry clear weather predominates 

 during this period, the method followed in harvesting and curing makes very 

 little difference. For example, in 1940, when the rainfall for August and Septem- 

 ber was only a little more than one third of normal, onions left on the ground for 



