Do you mean "creasy roots" (root mat) pathogen? We pin primary stem by needle with pathogen culture  just above root of tomato seedling and keep them at low temperature for several days. Others use inoculation by dipping plant roots for 5 min in bacterial suspensions of different concentration. (http://www.sipav.org/main/jpp/volumes/0207/020703.pdf)

If what you are trying to is to get hairy roots from tomato, I would inoculate tomato seedlings with the rhyzogene isolates. Germinate tomato seeds for 14 days (or as needed) on MS0 agar (with sucrose). Wound part of the hypocotyl at 1-2 cm above the surface of the media. Inoculate the wounded tissue with the isolate and co-incubate the inoculated seedling in common culture room. Maintain the temperature at 20-24C to slow down the growth of the excess bacteria under regular culture room lighting.

Once hairy roots are growing, isolate the roots and grow them in MS0 liquid medium (MS medium without growth regulator nor agar). Add the appropriate antibiotics into the media to eliminate rhyzogene contamination. Incubate the hairy root (5-10 roots per flask of 250 ml containing 50 ml of media) on a tissue culture shaker. If the hairy roots are transgenic carrying Ri-factors, they will proliferate on medium without GR. Otherwise, they will not grow. It is important to culture a number of hairy roots together in a single flask since a single hairy root tend to fail to grow.

We have tried this strategy on a number of cucurbits and hot peppers with a good success rate. Do watch for the bacteria contamination since the shaking may actually also promote the growth of the bacteria.

However, if hairy roots are not your target the propose methods may not be appropriate. Good luck...