In such a short time interval maybe Lettuce would be the fastest and easiest to grow?

Like Gopher I would recommend starter lettuce. You should be able to get baby lettuce at your local garden center or Walmart. Make sure they are the same size. Put one in your bubbler and pot the other in perlite. Don't use potting soil. There are too many variables introduced if you do (Affects of micro-organisms, trace minerals in the potting mix, etc.) So the variable you are testing is rate of growth in a medium (perlite) vs no medium (bubbler). Use the same nutrient to feed both plants, and expose to the same amount of light. Or you could use a different concentration of a paticular nutrient (vary NO3-) for example, or exposure to light as your variable. Just as long your are testing only one variable.

To those of you helping.....THANK YOU.

I have a plastic reservoir for my bubbler we are cutting holes into and some plastic baskets to 'plant' our seedlings into. Lettuce sounds like a great idea.

Could you explain to me how to plant the lettuce starts in the plastic baskets? Do I use some sort of wood chip or sp. moss or stones????? and how deeply do I place them into the reservoir?

We are going to keep the nutrients and light constant on both groups and the variable being only the medium/method of growing.

if your using hydro pots i would suggest growing in perlite. you can get it at walmart or home depot and it wicks moisture very well. Just let like a inch of the bottom of the pot in the water and perlite will draw up the moisture. you could also just put them in a piece of strofoam and let that float in the water just make sure the roots are touching the water in this kind of system. Make sure you wash off most of the dirt before you put them in. you should plant some in soil because growing in perlite or in a bubbler without a medium are both considered hydroponics.

Stellinate,
Check the link below. I just might help.
Ed

Here is a link that might be useful: Seedlings in bubbler

You have to be careful about putting seedlings in a bubbler  they can drown if they are too small. One possibility is to get some watercress or rooted spinach from the grocery store. The hydro system can root them further, thus extending the crop. The baby lettuce is a good idea  it will grow fast. If it is large enough it will grow in the bubbler without a media. Basil, tarragon, & mint will root in a bubbler, but except for the mint may take too long.
I will send you a few more ideas.