Your plants will not be poisoned by the use or RoundUp, since it is sprayed lightly on the foliage of the plants that are needing to be eliminated. There is NO reason for this chemical to ever touch the soil, whatsoever. However, even the smallest amount of mist can cause damage to desirable plants. Keep an eye out on your tomatoes and others for signs.

I personally feel that weeds in the veggie garden should be hand weeded and you should certainly remind him of that the next time he comes to your yard.

Thanks for the input. The grass has just started to die around the tomato plants. He might have caught a few leaves of the tomatoes but overall just the grass. I totally agree that weeds should be hand weeded...that's why I am so concerned - I never use chemicals near my veg garden...

Thanks again.