Ideally, you would reduce N applications to a bare minimum to put the brakes on additional vegetative growth while adding a K supplement. For example: Fertilize with 1/4 strength 20-20-20 soluble fertilizer every two weeks while adding a liquid K supplement at 1/4 strength at the same interval. There is WAY more than enough P in any 1:1:1 ratio fertilizer, even at very low rates. However, at these low rates (1/4 strength, bi-weekly) there may be insufficient K.

There is still time for good yields, but if you continue to apply high amounts of N, you'll likely continue to see luxuriant foliage growth at the cost of sparse fruit.

Al

I planted using Miracle Grow Organic potting soil. I've never added anything. Any suggestions?

How much sun are they getting?

Al

I haven't had any luck with Better Boys this year either. I transplanted three that I started from seed. Two grew very poorly, while one shot up to about 6 feet (set a total of 3 tomatoes). The leaves on all three then began to yellow and then dry out. All of my other tomato plants are thriving under the same conditions with the same soil mixture. This was my first time to plant Better Boys, and I must say that I'm not a fan. I have a few pics on my blog linked below.

Here is a link that might be useful: Container Gardening in the Desert

If you want to stop them from growing taller you could prune the main top branch off and then your growth will slow and become bushier.

do you want the plant to be every thing it could be or do you want to stop fert. and start pruning etc. how about cages.trellis.stakes.(i would let it be itself and contain it), and it will produce fruit!

I agree... some tomato varieties are simply larger plants than others, and if you want a smaller plant, you should look for a variety that is specifically bred for growing in containers.

Last year, I planted tomatoes in new raised veggie beds that were filled with a mixture of topsoil, potting mix, peat, sand, and a lot of composted manure and loam from my compost piles. I found that this mixture was incredibly rich... so rich, in fact, that the plants grew tremendously huge, but produced little fruit!

This year, I have my tomatoes planted in very large containers, and the medium is a mixture of regular potting soil and a bit of sand. I believe the yield of fruit will be much better! I have the containers sitting next to a fence, and they will be tied to that for support as they grow. The smaller varieties have tomato cages for support.

The rich veggie beds contain other plants that prefer heavy feeding! Lesson learned!