Help me diagnose my tomato plant's stem problem!

Question

I'm a beginner gardener, and growing tomato plants for the first time. I need help diagnosing a problem on my stems!

I regrew my three plants from seeds of a small heirloom tomato that I came across last year. All three plants are still indoors and small-ish. I labeled them in the below pictures as A/B/C. Sadly, the stems are all showing signs of deformity, though leaves don't have major issues (maybe a light yellow spot or two, which I plucked off). Plant C's stem was looking healthy until recently, and now it's starting to get that scabby look and lose its hairy quality in the affected area. Is this early blight? Bacteria?

Plant C was healthy looking until recently. Should I separate plant C from the others, or is it too late?

I've learned a lot already through this process and in hindsight probably should've heat treated those seeds. Would love help in diagnosing in the meantime. Thanks!

Answer 1

It looks like they may have gotten sprayed with something toxic to them, like a cleaner or disinfectant....it looks like it killed part of the stem.

That's a possible cause, the effect is some die-off of stem tissues, regardless of how.

Tomatoes will root all along the stems where they are in contact with soil. I've even rooted cuttings as an experiment.

To be safe, you could plant them deeper, with soil levels above the damage, they almost certainly root above the damage & quite probably be stronger.

if you unstake them and let them flop over naturally, the same thing will happen also.

Hope that helps