Hi Tris,
I agree with you on the nutrient aspect.
To compensate in part at least what I do is I grow in Potato Planter Bags filled with 50/50 Multipurpose Compost and well rotted Horse Manure. I then apply a liquid feed of Comfrey Tea about once every 3-4 weeks.
Watering is one of the key things to get right with Toms, and with mine growing outdoors, when I apply liquid feed is often determined by prevailing weather it being critical to maintain a consistent moister level in the bags.
This works well for me in that I generally get a very good crop of very tasty Toms from about end of July to the end of October.
There are cvrs available which are ideal for Pots, I tried Romello last summer. It only grows to about 45cm tall and wide and I had it in a 30cm pot. I was very surprised by the huge crop this little plant produced and will grow it again alongside my usual varieties this coming summer. Tumbling Tom is another which I grow in Hanging Baskets and they produce well also. I use the same mix and liquid feed in the pots and baskets as I use for the Planter Bags.
Obviously watering and feeding in these containers is even more critical to get right given their constrained size.
Don.
Don.