I'm not sure about the variety - do you think I should re-pot it into a larger container? These are the drainage holes in the container - http://imgur.com/a/xphtd

It's not getting a huge amount of direct sunlight as the balcony (and building itself) is quite shady. I've tried to place it in the best area for sunshine!

I'd just leave it as it is, unless it gets at least 5-6 hours of direct sunlight it's pretty much doomed.....sorry!

Looks pretty healthy, but yes, overwatering will cause root rot, and the lower leaves will be the first to go. Test for moisture as described. I sure hope it is a dwarf variety. Regular cherry tomatoes will make 12-15 foot vines, and that pot is far too small to support the mature plant. Not sure where you are, but if you're in a very hot climate, they will do OK with 3-4 hours of sun. You might get a few fruit with that pot.

I'm guessing you have more than one plant in that pot. Right? Each of those main stems looks like the vine from one plant.

I've just inspected the pot and yes, there are three plants in the pot! Do you think I should separate them out into three separate pots?

I'm in the UK, so not a terribly hot climate. I've placed them in the area of the balcony that gets the most sun, so hopefully they will be ok... There are a couple of fruits on one of the plants.

The kind of lower leaf wilting indicate to me dryness of soil. if you were watering too much you would get lower yellow leaves.

A plant that size in the size of pot needs thorough watering to make sure that all the soil in the pot gets soaked. This might me needed every three days or sooner depending on the temperatures and sun exposure.

Sey

When dry, my tomatoes wilt on top first.

Probably too late to separate. Those three plants have root systems that are now hopelessly entangled. But no worry. The three will produce as much as a single plant in that pot would have.

You could repot into a much larger pot, as those plants are certainly heavily pot-bound, but that will be challenging. Big job. The plants would certainly suffer in the near term from transplant shock, but would probably recover in a week or two.

If you leave them in that pot, as I said, you'll probably get some fruit, but nowhere near what the plants are capable of producing.

Thanks - I decided to re-pot them into a larger pot. You're right about separating them, the roots were definitely too tangled. Hopefully they will be ok in the long run!

I assume you're fertilizing them, yes? Get them as much sun as you can, and hope for the best. Poor sunlight won't kill the plants, but will make for fewer and poorer tomatoes. My cherries get about five hours per day, and I still get loads. The myth is that they need full sunlight. They don't. Cherries, I believe, actually need less light than large tomatoes.

Yes, I've been feeding them with tomato fertiliser once a week. That's encouraging about cherries needing less sunlight than regular tomatoes! I had a look at the label they came with, and apparently they are a trailing variety (which is why the container I got them in was a hanging basket, although I didn't have anywhere to hang them!).

With that in mind, do I need to think about putting a cane in the pot to support them ..or shall I just leave them be?

Well, cherry tomatoes are vines without tendrils. So people usually tie them up. No reason, I guess, why they couldn't hang down. But they will get longer and longer, and if you don't mind them just spreading out around the pot, I suppose they could do that. Tomato leaves touching the ground is generally not a disease resisting strategy, though.