According to University of Illinois Extension, summer is the appropriate time to dig and store tulip bulbs. During this period, the bulbs become dormant and their removal is simple and harmless. Store tulip bulbs in a well-ventilated area to prevent damage and to ensure their health during the next growing season. Hold off on separating bulbs until planting time to prevent disease and bulb damage.
Store tulip bulbs in an area that has a temperature between 60 and 68 degrees Fahrenheit, according to the University of Illinois Extension. Pack bulbs into a box or container filled with peat moss, sand, perlite or vermiculite to keep the bulbs dry and protected. They can also be hung in a paper bag or loose knit sack for storage. Avoid storing bulbs in locations that freeze, such as a shed or unheated garage, as this can damage the bulbs during storage. Do not store tulip bulbs in an area where fruit is also stored, as the ethylene gas produced by it can damage the bulbs.
Because crowding can promote the generation of heat that leads to rotting, never store tulip bulbs more than three layers deep, according to the University of Illinois Extension. Inspect all bulbs for signs of disease before storing and discard any small, undersized bulbs.