Most summer flowering bulbs and tubers should not be lifted until after the first hard frost.
The frost seals the tissue of the foliage and helps prevent fungal diseases. Although the foliage may look limp and withered after flowering is complete, it is very important to leave them in the ground so the plant can photosynthesize as much as possible. This helps the bulbs store up energy in its roots for flowering the next year.
Use a spade or a fork to lift the bulb and pry gently on all sides. The goal is to lift them without cutting or damaging the bulbs. Some bulbs are buried up to 6” below the soil so you may have to work around the roots a bit so they don’t get damaged. You can sift through loose soil with your hands to find them as well.
Cut off any remaining foliage and trim the roots.
Gently rub off large quantities of soil and wash bulbs with a garden hose to remove the soil on the bulbs. You can also soak them in a bucket of water to loosen the soil. It is important to rub off any loose skin on the bulb as this could cause them to rot while storing.
Inspect bulbs for signs of disease and keep only the large, healthy bulbs. Soft bulbs should not be saved. While inspecting the bulbs you can take the opportunity to divide the small bulblets that grow on the larger bulbs. These can be replanted the next year. Bulbs can be dusted with a fungicide such as sulphur dust to ensure extra protection from the development of fungus during storage.
Spread the bulbs far enough apart so they are not touching. A baker’s cooling rack or some window screen set on blocks will work. Let the bulbs dry for a day or two in a well-ventilated area. It is important to make sure they don’t freeze.
You can put the bulbs in layers of peat moss in a paper bag or card board box in a cool, dry dark place at around 7- 12 Celsius. An unheated basement will work. You will want to check the bulbs occasionally throughout the winter. Throw out any bulbs that have become soft or moldy.