Answer: After tulip bulbs have finished flowering in water, they can be discarded or replanted in soil. Tulip bulbs that have been forced to bloom in water may not be able to produce another bloom if they are replanted, but they may still produce foliage that can help build up the bulb for future blooms.
Explanation: If you choose to replant the tulip bulbs, you should wait until the foliage has withered and turned brown, which typically takes 4-6 weeks after flowering. At that point, carefully remove the bulbs from the water and gently clean off any debris or roots that may have grown in the water.