I have a few large trumpet daffodil bulbs that did not get planted. Can I grow them in water, they are already sprouting because I left them in under 30 degree temperatures.
We don't know where you live so can't say if you could still plant them outdoors, which would be the best course of action IMO.
The tazetta type narcissus can be grown in water e.g. paperwhite, soleil d'or, but I've not heard of trumpets in water. Possibly because they need a chill period whereas tazettas don't. I would put them in pots rather than water then give them the requisite chill before bringing them into the warm. In water it would be hard to work out a way of keeping them from flopping over as they grow so tall.
Remember too, that once you have grown them in water you will either have to throw away the bulbs or plant them in the garden after flowering to give them a chance to build up the bulbs for next year.
Here is a link that might be useful: Bulbs in water