With a careful selection of winter-flowering kinds, blooms can be had from Christmas through April. Plant bulbs in good garden soil in deep flats or pots, or directly into bench. Insufficient water is the major problem with iris culture if soil dries out at any time, there will probably be no flowers. Take care also not to injure roots.
Iris require plenty of air circulation and light, so space bulbs 2 to 3 inches apart and cover with at least 1 inch of soil. If your bulbs have not been precooled, pot them by mid-September and store at 50 F for six weeks for early flowering, or bury in a well-drained area outside the greenhouse.
Bring into greenhouse about November 15th and raise temperature to 58 F. If the familiar Wedgewood blue iris is treated in this manner, flowers will be available for Christmas, from the largest size bulbs. Smaller bulbs will flower later. Precooled bulbs should be potted or benched in mid-October. After flowering, water moderately until foliage dies back, clean bulbs and store for use the following season.