have you considered bugs and/or disease?
It could also be excess moisture, heat, or light. you need to record how long it is between changes in the environment so you allow ample time for the plants to work the kinks out.(i.e. note when you raised the lights, then wait "x" days to see if it is corrected)
Please note I don't believe its too much light. with flourescents, you're likely starving it of light.

The plant growth is very dense - nodes are very close together, and the plant is producing plenty of new foliage and roots. It seems to be getting plenty of light, as it is not bolting upward in search of light. I will keep record and give the plants 7 days to adjust to any changes made.

I guess it could be disease or bugs, but these were grown from seed indoors. Never in soil. I have not noticed any bugs and I inspect them daily.

I know there is a culture that loves to change nuits almost as often as babies' diapers but I never found a reason to. I've had plants in DWC for months (Sept-May, for instance) and never changed it once. Only top off when the level got low.

I also gave up on airstones. For reasons I have yet to figure out, they seem to clog after a while, even though the only thing going through them is duh, air! I use soaker hose that I weigh down a bit.

It may be neither of these factors are causing your curl. It may be something else - for instance, I use Tomato-tone ferts in the water and if I need to, add some Blood Meal for extra N, but only when the plants are young. A lot of TT's N is not water soluable.

Good luck,

Mike

wordwiz
If I read correctly you posted somewhere that you use Tomato-tone and blood meal for your nutrient solution. As far as I can tell these are both organic, and would help explain the longevity. Because organic nutrients are continually breaking down, providing more raw elements as they go. Also I have a feeling that adds to your air stones clogging.

Even though only air comes out of them they are still susceptible to clogging from everything that's in the water. Including non soluble particles, as well as algae. So just like a filter they need regular cleaning. Although I wouldn't use the thin round ones anymore. I'm not sure exactly what material there made of (it feels and tears like a tough paper), but for some reason those clog even with regular cleaning.

amcloud
What's the water temp? The curling leaves can sometimes be due (at least in part) by the water temp being too cold.

The house is stays between 70 and 74...70 is the coldest it gets at night. I imagine the water temperature is similar since they are just growing in a spare bedroom that gets plenty of air circulation.

That should be right in the ballpark. you were using lights so I figured they were inside, but thought they may be in the basement or garage where the water temp may get cold. I grew some tomatoes outside last winter, and had a similar problem. That is when I found out the cold temp of the nutrient solution could affect them that way.

In my case I believe that was a factor in the problem, but not the only factor. Tomatoes are susceptible to so many pests and diseases. I read up on it so much it got depressing. I trashed the winter tomatoes because they went down hill to much, then started some more in the spring. I still had a curling problem but nowhere near as bad, I also still had the insect problem which I suspect of infecting the plants with a virus. They were a combination of flying aphids and some type of mites. I sprayed them twice a week with NEEM and that kept there numbers down significantly, and then the new growth would grow out normal. But if I forgot to spray for too long they infest again and the new growth would come out curling again.

I also learned that not all of my tomato plants were affected the same way, so variety is a factor. I had 4 plants of three different variety's growing in the same system. One of them was not showing signs of curling, two of them were in the middle and the last one was the worst. But again with spraying kept it all under control when I remembered to keep up with it. But none of that may be your problem growing inside, although you could still have a pathogen or fungal diseases.

I don't use artificial lighting, so I don't have any first hand experience on if your lighting is adequate or not. I do know of one person that uses florescent lighting to grow all his plants including a couple of tomato's. Although he uses a lot of them. They are held by a wooden frame built around the plants, and are in a vertical position (up and down) like as if you attached it to the wall standing up. He has these lights on both sides of the plants. The fixtures hold two tubes each, and he has theme spaced about every two feet along the row of plants. If you already have the HPS lights, I would try using both the florescent and HPS at the same time to see what happens. If that works you can always move the HPS farther away to supplement the florescent, or add some more florescent lights. Depending on the variety and daytime highs in that room, they may even like the added warmth (or not).

hh,

My first grow, which went from early March to late June, I used EcoGrow. Last year's was the first time I used TT, though I also used some liquid bloom promoter as well as Fish Emulsion. I kept a 35 gallon garbage can in the GH and would fill it about half-three/fourths full of rainwater, add the nuits, adjust the pH and stick an aerator in it - no air stone, just a piece of tubing. I usually added about two quarts of solution per five-gallon bucket a week, on average.

Mike

I'm growing hydroponics toms in my GH without any artificial lighting and they have performed tremendously until this week, when the two oldest began to die (they were planted in late Feb). I reconfigured the air because I wanted to add more containers of toms and they didn't like it, I guess. I grow them in 5 gallon buckets and find that I added a quart of solution per day this past summer. Still at half of that so the plants are basically changing the solution themselves.

I experienced some curling and browning of leaves but since they produced so incredibly, I didn't worry. I want to expand to 10 plants so that I can keep my married daughters families' in tomatoes.

Mark

sounds like your E.C. is high to me in my experience most times when i get upward leaf curl it is from the nutes being to high for the variety

catmando6694
So just what EC reading guarantees the a balanced nutrient solution? For any plant. I'm not talking about freshly mixed nitrients, I don't need a meter to know that is balanced. I'm talking about well after that, say 2,3,4 weeks etc..

your absolutely correct about a meter not having anything to do with knowing your balance it is only good for knowing your strength i apologize that i didn't realize that your leaf curl was happening so long after adding your nutes i know lots of times people go right to the cal-mag deficiency line as a supposed cure all but i do believe that mag causes leaf curl also hope i've been some help if not sorry

Leaf curling is like a headache. It's a symptom and can be from any number of causes. Over watering, too high of nitrogen, poor lighting, low temps, insect damage, calcium deficiency (not to be confused with nutrients being deficient of calcium), etc. In such an instance I would check for bugs first and if there are no pests, then throw out the solution if it's over a couple weeks old or has fallout due to poor mixing practices. Make sure the water temps are good and that there is significant light. I have never had good results from tomatoes under T5's. Greens are great under them, though.

catmando6694
No problem, I wasn't sure what you meant. I have read so many times where some people feel that just by adjusting the EC/PPM/TDS readings in there nutrient solution, that that some how fixes a nutrient deficiency. I think that's mostly because they think the plants take up the elements evenly, when they don't.

Amen brother for me thats why i always empty my resivoir and start over every 14 or so days i know of no way to find out what percentage of each element is left in your recirculated nutrients and i know that will set you up to think you have a deficiency of one when you really have plenty it's just locked up sorry it sound like i'm hijacking this thread i'll stop now LOL

catmando6694
That's not hijacking, that's just how you have a conversation (back and forth exchanges). I agree with regular nutrient changes myself for that very reason. And also why I have not found a real need to buy a EC, TDS, or PPM meter yet. I can tell the relative strength of the solution by fallowing the mixing directions, but I usually mix a little week. Especial if it's, hot or the plants are small. Then I judge how long to use them for by the size of plants, and by observing how they look and plant growth, and/or ph swings (size of reservoir etc.). But I'll usually change them at 1 or 2 weeks (occasionally 3 weeks). Sometimes I will add some diluted nutrients back as well after the first week, especially if they are big plants.

Though I know plenty of people who like to use the same nutrient solution for long periods. I know of one in particular that uses a large reservoir (not sure the size, about 50 gallons or more I think), and dumps 1 or 2 gallons a day, re-adds fresh water, and at the end of the week adds some new nutrients. He uses it in a drip/dwc system with many different types of plants, and I believe last count was about 60 plants. He does this for months on end and says it works great for him. But he also uses a $1000 Growtronix to control his grow room, including the dumping and adding of nutrients.

I never changed nuits last year and I grew from September until April. I just added pH and nutrient adjusted solution to the DWC buckets.

Mike