~~~ My tomato plants have yellow leaves...only a few and only at the bottom...what is it? what do I do? ~~~

You can do nothing except observe since some yellowing at the bottom is fairly normal.

You can rule out and perhaps correct moisture problems (too little/too much).

You can spray those leaves with a foilar fertilizer and see if and how they respond.

So long as it is just few, at the bottom and stays that way, I wouldn't sweat it.

Could you post a picture of your entire tomato plant and some close-ups of the yellowing leaves? That would help identify the problem ... if there is one.

I generally cut those leaves off with a scissors. I would agree with Dave it is probably nothing but it could be some type of disease and I was always told to snip to stop possible disease from affecting other parts of the plant.

I actually snipped a few leaves which were yellowing this morning on my plants.

*deep breath* oh good... as you can tell I'm new to this and I didn't have it happen last year so I was worried... I try to take a pic tonight :-) Thanks so much!