Ethylene - Do not store flower bulbs with fruit such as apples or pears prior to planting. Ripening fruit produces ethylene, a gas which can cause "Flower Abortion" and other problems with flowering. Also, be certain to store the bulbs in open trays and if a refridgerator is used, to ventilate it properly.
"Nonprecooled Bulbs" - When fall planted bulbs have been purchased but not planted, they must be properly stored. Normally, they should be placed in a cool [55-65°F (13-18°C)], well-ventilated and ethylene-free area. Bulbs stored under these conditions do not receive any special preplant treatment and are called "Nonprecooled Bulbs". Unless specified, e.g., Fritillaria, do not store bulbs in paper or plastic bags.
"Precooling" spring flowering bulbs for utilization in USDA Climatic Zones 9 and 10 - Most spring and early summer flowering bulbs require an extended period (6 to 20 weeks) of low temperatures [35 to 50°F (2-10°C)] during the winter months to produce satisfactory flowering responses. Thus, there are two classes of spring flowering bulbs for USDA Climatic Zone 9 ("Mid-South") and USDA Climatic Zone 10 ("Deep South"). First, there are some "nonprecooled" bulbs that can be planted in the fall without any special preplanting treatments and which will perform satisfactorily either as annual (one season only) or as perennialized bulbs. Second, there is a group of bulbs that must be given a preplanting cold storage treatment in order for them to perform satisfactorily. These bulbs require 8 to 10 weeks of "Precooling" (PC), i.e. dry cold storage at 40 to 45°F (5-7°C) in an ethylene-free refrigerator prior to planting. These are subsequently planted in late November and December. For specific information on tulip cultivar performance in Climatic Zones 6 to 8, consult P.V. Nelsons 1988 Bulletin cited in the References. When planting spring and early flowering bulbs in USDA Climatic Zones 7 to 10 the bulbs should be planted in an area that does not receive direct sunlight from late morning to early afternoon. This helps to moderate the prevailing temperatures and provide a more suitable microclimate.