Looks tryable to me. I made a one plant cloner a while back using a 1 lb. coffee creamer container(about 1 Qt.), an air pump from a blood pressure tester and a piece of closed cell foam to support the stem. However if you want to eat tomatoes, I'm not sure if you would be able to get it to bear fruit with such a small space available for root structure. I cant tell from your picture how big that jar is. It looks like about the size of a 1 Qt. pickle jar? Maybe a 1 gallon pickle jar would be more viable. I think most hydroponic tomatoes are grown in containers 3-5 gallons or larger.

I also don't think you will like the results due to space for a large fruiting plant. Herbs would fair well, I'm sure. That being said, I'm only speculating. I'd love to see you try it and verify one way or the other.

The reason I don't think the project will yield well is that the root system will get too big (as hardclay was pointing out). To expand on why that is a problem, the roots will not allow for much nutrient solution to be in the jar eventually. The plant will drink the solution up quickly. I've had plants drink over a gallon a day on hot days. If the water level drops too fast, salts will also build up on the roots really fast. That creates further problems. Your pH will vary drastically, too. Again, just speculation here. Take good notes and let us know what your results are.

Yea I was afraid you guys would say that. Im still gonna try it just to see and will keep you guys updated. I planted a bunch of tomato seeds in my cocopeat nursery and most of them sprouted so Im running out of systems. One of them is gonna have to take it for the team.

i grow peppers in 3gal buckets and let me tell you that half the bucket is filled with dense roots when the plant is at full maturity. that little jar you have wont be enough.

I grow determinate tomato plants in 3-gallon buckets using DWC and they love it! Yes, the root mass gets a little out of hand, but as long as you keep nutrient solution in the bucket and air bubbling inside, it works like a champ!

By the way, I use welded-wire plant supports with 4 vertical posts and the bottom support circle is almost exactly the same size as the lid on the 3-gallon bucket. I drill 4 holes each 90-degrees apart and insert each of the 4 wire legs that would otherwise be jammed into dirt if I were growing in soil and support the top of the thing on a south-facing fence (which casts a partial shadow on the plants during the heat of the day) and the plants thrive!.

Root (versus shot) size is also related to nutrient composition. The better (actually the more balanced) the nutrients are, the smaller the root size would be. Well, in fact it's the other way round - if the solution is not balanced or too poor in nutrients, the roots tend to expand much more. If all conditions are just perfect, (including PH, temps and oxygen content) a plant can thrive perfectly well (bloom and fruit as well) with a relatively small root mass. Also, you can actually trim (the ends of) roots at any time.

I have one little Tomato plant thats not growing at pace with the others. Im gonna try to catch him up with this. Its not the prettiest system, I wrapped in Duct tape to keep the light out, not sure if that was necessary or not?

Good idea. It should help with preventing algae growth. That little system might just work to catch it up with the others.

These are the other plants I am trying to catch this guy up to. As you can see he's got a long way to go. Im gonna have to transplant these ones soon.

Just a quick update, I havent added more water to the above system(the duct tape bubbler) and the roots are keeping exact sink with the depleting solution. It's so cool. Im not seeing any growth up top yet but am definitely seeing some root growth.

I'm SO curious on how this will work! (and it doesnt need to be pretty, it's suits the purpose!) LOL

Lol it's definitely not gonna win any awards for looks, thats for sure. I'm getting nervous though because I just noticed the big plants are starting to turn a little yellow, I haven't even tested the ph yet(brand new to hydroponics) Gotta do some research. thank god for this forum!

I'll take function over looks ANY day. Just sayin lol