Far from ideal but you have to use what you have to work with. Is it possible? Yes, the plants will be leggy and not as productive but it is far better than nothing. No, I wouldn't count it as part of the 6 hours.

Dave

Someone gave me a big fat patio tomato plant last year...it had been in his car for a couple weeks in Brooklyn...a parking lot hand-off..."here, take this thing....i don't grow plants..."
So i plopped it in a pot in my driveway with zero care...moved it a couple times for better sun as the sun shifted...it did swell for what i gave it. Don't stress over it...do what you can and learn from it...
I'm not at all a container gardener as my garden is on a farm upstate from the city home, but i do understand that method of using containers and moving what you have...for better sun.
Just keep paying attention to the sun shift...as it moves back down...
Your own growing conditions are personal and based on a bit of experience...

Speaking of my personal experience, 6 hours of DIRECT sun plus INdirect light during 14 hours of daylight (we get up to 16 hours here) tomatoes should be fine. Maybe not ideal but still practically doable with success.

Direct sun is more intense (in terms of lumen, candle light..) but indirect sun, defused sun also counts as light. I have read this somewhere that intensity of light in an overcast day is almost equal to what plants get under fluorescent light. So do not count out indirect sun light. Plants (tomatoes in this case) need certain amount of light (in total quantity) to do their photosynthesis. Beyond that direct sun acts just a heat source. In some locations that is even harmful. So they shade the plants to get just about 40% -60% in terms of lumen.
Another Point: By definition 6 hours is considered full sun, although at the lower end.

JMO

Yeah, it has been trial and error. I have also contended with black flies, green/red/black aphids, soap burn, neem burn, huge fungus gnat infestations, and (currently) early blight. The fungus gnats came in on the potting soil I used (some kind of miracle grow organic?). I had to go nuclear on them- crumbled mosquito dunks in soil, sand on top, neem spray on sand surface and bottom of pot. I only see about 1-2 a week now (if that) so I've been removing the sand and filling up the pots with soil so the plants can use that space to grow roots.

I know that the plants still get indirect light in the shade, but I also made a grow light in an effort to supplement them with additional light. I got an aluminum hooded light and put one 100 W equivalent 2700K and one 150W equivalent 6500K CFL (totaling about 4500 lumens) in it and every day I hang it above the plant I think needs a little extra help for about 12-16 hours.

At any rate, here is the progress so far. All were planted in mid April except the Eary Girl, which was planted in late April but already had a mater on it. The yellow pear cherry just started ripening some tomatoes and has about 40 on it. I know most people think those are bland but the plant is so damn pretty. The red husky cherry has about 90-100 on it and has ripened maybe 10 so far. The early girl ripened one about 10-14 days ago, has 4 full-sized green ones and just recently put out another 5 after a hiatus. The patio tomato put out 22 tomatoes, ripened one early, then stopped. It is determinative and has been done flowering for quite a while. I've been eager to ripen the tomatoes and be done with it because now it's harboring disease, taking up space, and wasting copper spray. So I removed half of the tomatoes and tortured it by poking the roots with a stick to scare it into ripening (which made me feel like a bad person lol). It has started ripening again, and tonight my husband and I sliced and fried the green ones, which were delicious. So even if they never ripen I'll just feed myself fried green tomatoes.

Which brings me to another thing I have been wondering about. Is it normal for tomato plants to ripen one or two tomatoes and then stop for awhile before ripening the other ones? I'm not sure if my plants have been like that because they've been battling disease or if I'm just being impatient. It's like they are teasing me.

if the tops are getting sun, can you put something under the container to raise it up ?
maybe a mirror ? :)

For me in New Orleans, we get too much sun. the ones i have in the ground in full all day sun, get too hot.
most varieties stop growing in the dog days of summer here.
then pickup in the fall again when it cools off.

black containers dont help, they can heat up the roots with a lot of direct sun in the summertime...

Please think about a large plant that gets NO sun on the lower part of the plant b/c of the foliage cover. That's the norm for almost all varieties I've grown, and most of them by sprawling or caging and more recently in containers.

Sun is important for photosynthesis to occur and that process makes the energy compounds that are involoved in all aspects of tomato growth, blossom formation, fruit set and maturation of fruits.

Fruits do not need sun to ripen up.

aphid, any tomato plant I've ever grown has buds, blossoms and fruits in all stages of ripeness, so no, I've never seen a plant that ripens just a few fruits and then stops for a period of time..

Carolyn

There is a wealth of information about need for light by tomato plants but little is known about absolute thresholds for growing. I acted against the advise of a plasticulture expert and Horticulture professor in using shade cloth over 2 high tunnels of tomatoes last summer and the results were great. I will repeat the method again this year, not to limit sun but to hold heat (produced by sun) to a more tolerable level.

as for plants producing a few ripening fruits and taking a break I see it now in many potted tomato plants that I have remaining for sale. Stress will cause many tomatoes, peppers and other fruiting plants to ripen the few fruits established rather than putting on more vegetative growth- Carolyn knows that since she just commented on it a a recent thread. It is not a big issue with cherry/grape varieties and it gives the plant buyer/grower the unique opportinity to see what type of fruits the plant will produce.

Thanks everyone, for taking the time to comment. I've been reading a lot on these forums in the last couple of months and you have all been really helpful.

I know that the tomatoes need heat to ripen rather than sun, so I figured that it wasn't that. The break in ripening and flowering happened around the same time we got a bunch of rain and I was fighting fungus gnats and then early blight on all of my plants. Since I have been getting those two things under control they have been blooming more. It was probably the stress of that.

On the flip side, I have been trying to stress out the patio tomato so I can be rid of it already. Every day I go out and cut off a few more leaves and stab the soil a little more while saying "vee have vays of making you talk." It is ripening two now, and it looks like a couple are going to start. We have designated that corner of the balcony Plantanamo Bay.

As far as maximizing the sun goes, I mirror might work. I tried to make a reflector out of what I had on hand (cardboard and foil) but my one cat found the corners too delectable. Cats are supposed to hate foil, but this cat, well, she's our "special child."

At this point I'm going to stake them with longer stakes to support the high branches so they can continue breaking into the sunnier areas.