Ryan, that happened to me one year when we had a very wet, cold Spring. I ended up losing all my tomatoes except Pruden's Purple. I believe it is a blight of some kind brought on by those conditions. I am sure there are people on here that deal with it all the time that can help you more than I can.

Please tell us what your weather conditions have been. It looks like it is in a pot. Do you have potting mix or regular dirt? Are there drainage holes in the pot? I am just asking questions that will help others to have an answer to your problem. :)

Rebecca

Thank you for your input, I am in a sub tropical climate, growing indoors using a soil mix with lots of beach sand in a pot with minimal drainage, I'm close to the ocean. i have Been watering this plant everyday.

Ok, Ryan, here's the remedy in addition to what Linda says... Cut 2 holes for drainage, and water only when the top of the soil up to your first knuckle feels dry. You might want to start new tomatoes using potting mix from the store that is sterile in a pot with drainage, with some added fertilizer. Lots of beach sand is too heavy, combined with lots of water and no drainage is drowning your tomato. Do you plan on moving your tomato outside?

On a totally different note... Love the close to the ocean part!!! :)

Rebecca

Agree with Rebecca's advice. You don't want a mix with "lots of beach sand" and you do want to have good drainage, not "minimal drainage". You also probably don't need to be watering every day. For very young seedlings, I always water from the bottom in a way that the water is absorbed into the container from the drainage holes at the bottom. Once they've grown to the point where they've become nice sturdy healthy seedlings, I'll begin top watering but only AS NEEDED.

It is a fungus stem rot commonly caused by one of 3 or 4 various soil-borne fungi. Probably pythium in this case but no way to know for sure without culturing it. See article linked below. The original problem/cause was using soil/dirt/sand in the container rather than a soil-less mix. That is never recommended as it is not sterile, already infected, and creates the perfect conditions for the fungi to multiply and infect the plant. It is then further compounded by way over-watering poorly draining soil. The roots become infected and it progresses up the stem to slightly above the soil line and into the circulatory system of the entire plant.

Saving the plant is very unlikely once the symptoms develop to this degree. Sorry.

Dave

http://plantdiseasehandbook.tamu.edu/problems-treatments/problems-affecting-multiple-crops/stem-and-root-rot/

There is another way to save the plant! Cut it off and root it in water then, when the roots are big enough, transplant into the correct (potting soil) mix.

Linda

Thanks, Dave, for answering that so well.

Linda, I never knew you could do that with a tomato, but it makes sense with all thoses little cells that readily root on the plant.

Rebecca

How does the top of the plant look ?

I would nip those lower leave anyway. The are touching the soil.

I have seen many plants that their stems at lower part were thinner than further up.

Sey

Dave is correct, I had this problem a few years back...replanted a couple times in the same area and the new plants did the same thing. I ended up planting tomatoes in large pots and placing them in those spots. The stem looks like it's turning woody; an otherwise healthy-looking plant just keels over at the base.

I had a damping-off problem a few years ago and this is what they looked like. I would dump that local sand, grab a bag of seed-starter and start over if you have time. When I had the damping-off, I tried to pile up "good" soil mix around the seedlings as a last-ditch effort. Once that fungus gets them, best bet is to trash the tray or whatever you are growing them in and start over if possible. I had to ask some questions which seemed embarrassing to me but found out that there are several fungus problems that cause your plants to do this. They need air, I have always used a fan from day one. Water from the bottom. Lori