Bato Bucket Size Question

[budbon]

I am getting ready to set up bato buckets using drip. I recently acquired a number of 2 gal buckets. What is the criteria for determining what garden plants could be grown in these? Tomato's, peppers, strawberries, etc. Is it necessary to have a larger root space or is that a consideration in that the plants are being fed the necessary nutrients and should not need to spread out seeking these nutrients.