Posted: 24/06/2013 at 07:30
NewBoy, Dove is right. Sweet Millions is an indeterminate, it can grow to 6' or more if allowed, meaning it has an extensive root system. Your plants are already telling you they need more room for their roots.
Indeterminates need at least 30cm pots, preferably bigger, if they're to reach their potential. But pot depth is even more important for indeterminates. The plants will be need to be staked and tied up to the stakes as they grow. Too shallow a pot and there will be insufficient soil to keep the stake stable. The first strong wind will blow the stake out of the pot and take the plant with it. Look for pots at least 35cm deep and sturdy stakes. The stakes will be carrying/supporting a decent weight as the plants grow up.
You can control the height of an indeterminate by nipping out the growing tips - the tops of the stems that are growing upwards. They're called the "leaders". They're easy to identify. They're the ones producing new foliage and flowers, not the side branches.
When you nip them out depends on how many toms you want. Indeterminates continue to produce foliage and fruit as they grow during the season. Once you stop the plant growing, that's the end of your ongoing fruit production. You'll harvest only from the trusses that have already formed below the point where you stop them growing.
You've got 7 plants, they're a productive variety. You have to decide how many toms you want the plants to produce. Or you can just let them grow through the season and harvest the results.
All Dove's advice is excellent. Nip out the suckers/side shoots that develop in the intersections of the main stem(s)/leaders and side branches. Left to grow, they will form more growing tips which will become leaders themselves. The rule of thumb is that two leaders is sufficient.
Don't overwater - let the mix in the pot dry out between waterings - and don't over-fertilise. Toms in pots don't need fertilising more than once every three weeks. Toms produce best when treated with controlled neglect. Over-watered and over-fertilised plants are less likely to produce at their maximum, and, in fact, are more prone to disease.
Hard to know what's going on with your lower leaves without seeing a photo. It could be the plants' roots protesting about the lack of space in the pots, could be the early stages of a fungal infection. Can you post a photo?