Some type of fungus disease. Reduce the amount of watering and add air circulation. Probably not possible to save it but you may be able to enjoy the one tomato. Do NOT put the soil on your garden if it dies. Toss it and the plant directly into the garbage.

Probably you are having warm days (and some nights) now. Would it be possible to take it outside to get that undiluted-by-glass sunlight for short periods, bringing it back in when it gets cold?

Probably a good idea to put it in the shade for a few periods, maybe after several such periods letting it get full sunlight late in the day, near sundown when the sunlight travels through a lot more atmosphere before hitting ground?

When I start seeds in pots for transplanting, I sow them in holed cookie trays and put them on a wheeled platform that I pull out in the day and haul into the garage on frosty and chilly nights.

ole joyful

Have you fed it? Compost and compost tea can be a tonic for ailing plants.

Unfortunately, volunteer tomatoes may not be the most healthy specimens. I sometimes let them grow as an experiment, but they don't always survive, and those that do never seem quite as healthy as the parents. Unless it's seed from an open pollinated or heirloom variety, it's usually a roll of the dice what you'll get.

Thanks everyone for your helpful feedback. Maifleur, I‘m going to follow your caution and will trash in any foliage and not reuse the soil for gardening.

olejoyful — clever idea for your roll out/roll in planter.

carolb, i agree the seed is probably some ratty undeserving mutant. I’m viewing it as an experiment. I’m going to give it a haircut, repot with new potting mix. Maybe add a bit of fertilizer with minerals. I may even get to Sal age some of the Thai Basil that got taken over. I have a bit of dilute “near edible” orchard spray that I put on some seedling to prevent damping off. Oh, and maybe circulating air. I just don’t want to infect any other plants. I’m thinking ii is a mineral deficiency, since the nearby geranium, fern, ground cherry and sage look healthy.

I run out of energy so easily. Big ambition, no oomph!

At least spring is here, finally.

oh, and carolb, I hope you’re not near Piney Point. What a horrible mess In such a gorgeous area.

It looks a little bit like the beginnings of early blight. I would remove any affected lower leaves and spray the plant with an anti-fungal spray. You could mix a small amount in a spray bottle. Sterilize any tools that have touched the plant. If you can segregate the plant or put out in a sunny location for a few hours after spraying it would be good.

Haha Richard, I do the same and got a pretty good one last year - or maybe that was the year before. I have a couple right now I let grow from the remnants of a compost heap I moved. 1 has little grape-sized fruits with a point, and the other has several egg sized round fruits. Another had strange tiny double lobed fruits that tasted great - they tend to have tough skins tho.

FYI, Piney Point is in the next county over, but the discharge is very likely to affect our shared coastal waterways. We're surrounded by water here - between several bays, including Tampa Bay, and the Gulf of Mexico.

Carolb, you bring up a great point. Shared bays, coasts, planet.

Years ago, I got better “accidental“ veggies from my compost heap than from the garden.

we had a dishwasher adventure yesterday, so that Tom plant got ignored. It might have to wait for herd immunity (“heard immunity?”).