Cut the spike when the first floret is showing color. To cut the spike, insert a sharp knife above the second to fourth leaf and make a slanting cut up the stem. Immerse in water immediately to prevent wilting of the petals. Be sure to leave at least two, and preferably four, leaves on the plant after cutting spikes to help corms mature properly. Gladiolus spikes are very geotropic and should be stored in a vertical position until they are used.
Corms are ready to dig in four to six weeks after blooms are finished or when the tops die off.
They can be dug anytime before a hard freeze. Healthy plants should be left in the soil as long as possible so there is ample time for maximum development of the corms. Curing and cleaning. After digging, wash off soil that adheres to the corm and roots. Cut the tops to within one-half inch of the corm.