The ideal time to harvest the flowers for drying is just before they become fully open, on a fine, dry day. Do not collect them when it is damp or if they are still covered with morning dew or they will become moldy and discolored and will nor dry properly. Cut the stem with a sharp knife, making a sloping cut through the stem or flower stalk. Lay the cut flower heads and stems in a dry container but don’t fill the box too full or the bottom flowers will become crushed and bruised. Work on a bench or table to sort through the flower stalks, removing any large leaves from the bottom half of the stalk.
Most flowers can be air dried but some are more difficult than others. It is a slow process that often takes up to several weeks. The best method is to hang the flowers upside down in small, loose bunches, tightly tied at the base with rubber band, in a dry, well-ventilated place, away from direct sunlight, or the flowers will fade. Do not use string to tie them up as it loosens up as the stems dry and shrink. The remaining leaves will dry in about 2-4 weeks, depending on the plants and how dry is the atmosphere, and the larger leaves will shrivel. Once this happens tap gently the bunches and move them from the drying place and store them by hanging them in a cool, dry place until you will need them.
Some plants can be dried in a microwave oven to speed the process. For example, a rose flower will dry in about 2 minutes and 50 seconds, compared with one week with air drying. But keep in mind that dried this way the flowers become more brittle.