I don't see why it couldn't be done though I'm also not sure what the benefit would be either.

They would be easy to bottom-feed if you had a stand or support??

They would provide an easy device to transplant.

Here is a link that might be useful: My Hydroponic Adventure

I've started seeds in 1" plastic straws with a perlite/vermiculite medium before. ease of transplant was the driver for the experiment. From that experience, I don't think it is worth the effort. you're better off starting them in a damp napkin and using tweezers to move them to their final resting place.

Thanks! The whole idea...there are some things that do not transplant well, like beets - I have heard carrots also do not transplant well. I would like to use something like gravel as a growing media because it is cheap and readily available but I don't think that beet or carrot seeds will grow from seed in gravel. The idea is to put them in a container that is favorable for sprouting and initial growth and then have the container self destruct in a couple of weeks, when they sprouts are able to fend for themselves in the gravel. About 20 years ago I used to buy some seeding pots made of peat moss - peat moss that had been pressed and formed into the shape of a cup. I planted my tomato seeds in the cup and then, when it was time to put the plants outside, just dug a hole in the ground and put the whole pot in it.