I am a lazy gardener so this is what I do. Bearing in mind the bulb uses the leaves to replenish it's strength to bloom the next year, I wait until when I gently tug on the foliage it easily lets go and comes off in my hand. To test, tug gently on one leaf stalk at a time. When the bulb has reabsorbed the energy it needs, the leaves will easily pull off of the bulb even though they may still be green. I find this generally takes about one month after the plant has finished blooming. If you have 25 of the same bulb, once one is ready, they probably all are so you don't need to gingerly test them one at a time before pulling to remove the leaves. If you want to increase little bulbs like snowdrops, Siberian squill, grape hyacinth, etc. wait until the seed pod stalk begins to droop toward the ground. Now it is ripe and ready to plant. Collect these seed pod "flingers," and toss them wherever you would like more bulbs. In about three years these self planted bulbs will be big enough to bloom. No work to plant, these free bulbs can't be beat.
I am a lazy gardener so this is what I do. Bearing in mind the bulb uses the leaves to replenish it's strength to bloom the next year, I wait until when I gently tug on the foliage it easily lets go and comes off in my hand. To test, tug gently on one leaf stalk at a time. When the bulb has reabsorbed the energy it needs, the leaves will easily pull off of the bulb even though they may still be green. I find this generally takes about one month after the plant has finished blooming. If you have 25 of the same bulb, once one is ready, they probably all are so you don't need to gingerly test them one at a time before pulling to remove the leaves. If you want to increase little bulbs like snowdrops, Siberian squill, grape hyacinth, etc. wait until the seed pod stalk begins to droop toward the ground. Now it is ripe and ready to plant. Collect these seed pod "flingers," and toss them wherever you would like more bulbs. In about three years these self planted bulbs will be big enough to bloom. No work to plant, these free bulbs can't be beat.