I am assuming that your plants have actually grown since March. If not, then you have some serious stressor. If yes, then you may have overapplied nitrogen fertilizer. But also poor illumination (as in, not enough sunlight) can have this effect.

They have grown - about 3 feet tall now and I have not fertilized them, but they are growing in commercial potting soil.

I though the potting soil had some in it.

Re your friends, they may be growing a different variety, under different conditions.

Your tomatoes are not getting enough heat and light.

Potting soil has a limited amount of nutrients to begin with, if it has any at all. What doesn't get used up by the plant is easily washed out of the container when you water. Potted plants need fertilized more frequently than plants growing out in a garden.

Rodney

If You decide to fertilize, there are different fertilizers/formulas.

I think if you use the wrong fertilize, it will cause a set back, I.e., grow leaves vs fruit.

I grew tomatoes commercially for 5 years.

The plants look like they grew pretty well. They weren't suffering lack of fertilizer. Certainly productivity would be improved by fertilization, but lack of fertilizer won't explain lack of flowers. In fact, fruiting plants often respond to stress by trying desperately to fruit.

These plants are getting the same amount of heat as those of the neighbors, but may not be getting enough light. Hard to tell from the picture whether they look etiolated.

To me, they look like they could use some extra light (not necessarily because of legginess). They are on a porch, after all. I'd personally give them some phosphorus (and some extra sun), whatever else you give them. What kind are they? Adding phosphorus to container plants does help flowering, in my experience, and it helps plants mature faster. However, in a shady area, it might make legginess worse, if anything; so you'd want more light' I believe. They're not a terribly dark green; so, they might need general fertilization, too.

Phosphorus in soil doesn't just disappear. Inorganic phosphorous, which is the plant-usable kind, is actually produced by microbial action on organic phosphorus, which comes from all the organic material in the mix. Phosphorus doesn't "run dry". Leaching doesn't really remove that much phosphorus, unless the soil is near saturation in the element. Phosphorus deficiency has effects that are much more serious than lack of flowering. Purple leaves? Large scale stunting? I don't see it.

Oh, so the plant pulled *almost* all the phosphorous out of the soil. Left just a bit to confuse us. Gosh, aren't plants tricky? I suggest you get some education in soil chemistry. That's not how it works. But I'll be done here, since it seems it's all been figured out. I guess the OP should blast the plants with P and see what happens.

These guys above know much more than I do, but what about temperatures? Fruit set doesn't do well above about 90*. OOOOh ! Now I'm worried about MY maters! Having a heat wave!

Upstate New York heat wave? Also, the OP says that his friends (presumably local) are seeing flowers. Yes, fruit doesn't set at high temperatures, but the plant will still try to flower until the temperatures really get extreme. Oh, I said I was done. Oops.

To say that the lack of fertilizer given to these plants is not a major cause of the plants not flowering is absurd. The fertilizer that was in the potting soil is gone now. 3 months feeding is what is usually listed on many bags of potting mix and the nutrients never last near that long. Yes, the plants initially grew okay because there was still nutrients present when they were younger but the plants have since stalled out.

I see it routinely in my own tomato plants and seedlings when I have extras that I have no space for. If I don't fertilize them then the first thing the does is stop growing much if at all and the leaves/stems start to take on a yellowy green color (which it looks like the OP's plants are doing, unless the color is off in their photo). The next thing that happens is the leaves will start to discolor further and spots will show up as the plants move the available nutrients from the older growth to the newer growth. And no, they never try to flower from this stress.

Also, depending on the brand of potting soil used the amount of fertilizer present is almost nil. For example, Vigoro brand organic potting soil says it feeds continuously for 3 months but yet it contains a miniscule NPK of .09-.06-.09. It's basically compost and we all know how well that does in containers.

I agree with gardengal that a general all purpost fertilizer is needed. Not just one specific nutrient.

Rodney

Could overcrowding in the containers be a factor, also?

I'll let you decide, but I have a best boy plant growing in a 5 gallon pot at another location I care for right now. The sweet elderly lady wanted to use the pot so I reluctantly agreed and continue to fertilize it, and added a 24 hr drip irrigation line to it. With only 4 hrs of direct sunlight the plant is 6 foot tall, with thick stems and foliage saturated with 20 to 25 tomatoes on it. I can't stick a finger down a 1/2 inch because the root ball in the pot is packed tight, I have to compensate with additional feedings but is doing great.

Yes, if you have multiple plants in each container, that could certainly hamper the maturity and flowering, especially if they're in shade or partial shade, but in full sun, too.

I would suggest thinning to one plant, per container, with scissors, unless you're breeding them, you need more plants (for the genetic diversity), and you only need a few fruits per plant or something. Pulling up the roots of the other plant isn't necessary, and could harm your remaining plant (just cut down the extra tomato plants). Your remaining plant will probably double in size pretty fast after thinning.

Okay, I have to chime in on this can of worms. Many on here insist that fertilizer is a must constantly, seemingly for anything and everything. The only thing I've ever fertilized is my Aerogarden (and I'm bad about being "on time" with that). I get flowers; I get tomatoes, etc.; plants don't come here to die (unless they're astilbe); and generally everything grows fine and is the color it's supposed to be. All my tomatoes and peppers grow in pots, usually 11"-14" pots, which most probably think are too small, and they get planted in regular potting soil (usually Miracle Gro, sometimes Coast of Maine) and just get tap and rain water. Now maybe our hard water is supplying a little bit of something, but it's certainly not fertilizer. The biggest issue I've had is planting going over in wind. I'd be happy to add picture if anyone wants to see the monsters we've got growing with plenty of flowers/fruit and no fertilizer. Fertilizer might increase crop, but no flowers seems like there's another issue.

What variety tomato are these plants? It may be a later maturing variety. How much sun do they get? That could be different from your neighbors' plants and affecting flowering.

They get about 3 hours of morning sun and then reflected light off the neighbors house in late afternoon. They are grape tomatoes which I started from seeds of grocery store produce.

The amount of sun sounds questionable; they'd like at least six hours of sun. I'd be more concerned about the plant not being from known seeds, though, since they just came out of a grocery store tomato. The tomato varieties for which they sell seeds are selected for their productivity, size, flavor, and various other features. With the unknown seeds, we can't know when your plant is supposed to have tomatoes (though most varieties have at least flowers at this point); your plant may also may not be a great producer, or may be essentially sterile. We also don't know how big the plant is supposed to get and whether it's behind on that and this just not big enough to produce, yet. My Chocolate Cherry plants were still babies and just ready for transplant when they were the size of my Extreme Bush, which is mature and producing at 2 feet tall.

The simplest test will be to put it in more light, but you might consider ordering known seeds for next year, which also lets you select attributes of your plants, such as being container friendly.

They are in galvanized tubs. Would that be a factor?

debodun, I'm in CNY so know your conditions. Your tomatoes will do much better if you can place them where they'll get more sun. When in containers, I also try to remember to fertilize often with a very weak solution of Miracle Gro. Do the galvanized tubs have holes in the bottom for drainage?

daninthedirt, yes! Until just this Saturday, it's been in the 90s for many weeks here and we've had a total of .2" of rain in all that time. We finally got a good soaker on Saturday thanks to the tropical storm that moved in.

The fact that the seeds are from grocery store tomatoes may also be a factor. If the seeds were from a hybrid variety, if it produces fruit, it may not be similar to the original grocery store variety.

The containers do not have drainage, but I try not to over-water. It's so warm that they dry out quickly anyway.

You need holes, no Buts or alternative reasoning allowed on the subject and not negotiable. You may as well throw the plants in a lake because its what your doing to the roots, they drowned and die.

Checked today. I feel like giving out cigars!

There you go! It's growing tomatoes now! Did you change anything? Or is it just a late bloomer?

Didn't change anything to my knowledge. The other plant is still dormant in regard to flowers.

If they're from the same seed source, they'll usually run on a similar schedule, so hopefully it'll be blooming and fruiting, too, in another day or so.

I've just started picking my cherry and plum tomatoes, so they're not hopelessly behind. You should still be able to get a fair amount of tomatoes if this one keeps going and the other one joins in.

I'm picking mostly my 65ish days to maturity varieties. There are small tomatoes that can be closer to 85 days to maturity without there being anything wrong with them ... you might have something more like those.