UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 797 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 



Washington, D. C. 



November 22, 1919 



COMMERCIAL DUTCH-BULB CULTURE 

 IN THE UNITED STATES 



By 



DAVID GRIFFITHS, Agriculturist, Office of Horticultural and 

 Pomological Investigations, and H. E. JUENEMANN, Super- 

 intendent of the Bellingham Plant-Introduction Field Station 

 Office of Foreign Seed and Plant Introduction 



CONTENTS 



Bulb Production in the United States . . 1 



Soil Adaptation 3 



Temperature, Soil, and Fertility Require- 

 ments 4 



Number of Bulbs Grown per Acre ... 5 



Planting ^ 6 



Depth of Planting 9 



Treatment after Flowering 10 



Roguing 10 



Harvesting the Flowers .11 



Cultivation 11 



Harvesting the Bulbs 13 



Storing and Curing 14 



Cleaning 18 



Sizing 20 



Page 



Advantages of Sizing 22 



Culling 22 



Propagation 23 



Determination of Flowering Quality . . 26 



Packing Bulbs 28 



Shipping Bulbs 28 



Bulb Growing for Pleasure 29 



Miscellaneous Bulbs 33 



Bulb Pests 33 



The Best Varieties to Plant 36 



Varieties of Narcissi 37 



Varieties of Tulips 41 



Varieties of Hyacinths . . . . . . . 46 



Bulb Literature 47 



Definitions 47 



WASHINGTON 

 GOVERNMENT PRINTDJG OFFICE 



1919 



