Continue nurturing them until the leaves yellow and collapse. Dig them up and dry them in the sun for a couple of days(protect them from animals while drying),When you are sure no moisture remains,(I always wash the bulbs thoughly BEFORE drying)store them in mesh bags with good air circulation. I hang my mesh bags in my basement in a cool dark area. About the first of September I go though the bulbs and only save those 12cm in circumferance or larger. Smaller than that they usually won't bloom. The saved bulbs I put in my garden refrigerator,in the same mesh bag, until planting time, about the first week of December. Al