Tomato plant dying from the bottom up

[familyblackout]

This is my first tomato plant, grown from seed. It is a couple months old and I am so proud of it. However, in the last week or two, the bottom leaves began to yellow and wilt, eventually just dying on the plant. Just yesterday, the next leaves started to yellow. I have looked up some diseases, but honestly I do'tn think it has any. Could I have over-fertilized it? It is in a pot, and I did accidentally overfeed it a couple of weeks ago, but I applied the same amount of fertilizer to some seedlings in pots, and they are doing fine.
I know this isn't very much information, but if you can help, I'd be so grateful!

[NicJean]

Tomato blight is rampant in VT right now, last year several states had it. It's a (mold) type disease and works very fast. (Typically leaves yellow then turn black) OR you are over watering. As a former florist/Greenhouse manager any yellowing typically means too much water (my gut reaction). Just a thought.

[frugalfranny]

My first thought was over watering too............if the main
stock/stem of the plant still looks okay...........

Let it dry out between watering..............put your finger down in the soil about 2 inches or more.........if that much is dry (totally dry) then water.............and water until it runs out the pot..........THOROUGHLY.

Do you have blooms? fruit? Do they look healthy?

[RaineyDaye]

I think I have something like that this year on my tomatoes. After looking up tomato diseases, I think mine have "early blight". I cut off all the bad leaves and branches. Oddly, I still have flowers and tomatoes being produced, but they aren't doing great.

[familyblackout]

Oh, wow, thank you all so much! I had reviewed the diseases in a little tomato book I had, but there were no pictures so the blight didn't sound right. I looked it up after you all mentioned it, and it seems really similar! I guess I'm a little confused, though: I used organic potting soil from a bag (I did put rocks from my driveway on the bottom of the pot when I transplanted)- how did the mold show up? Am I being really silly in assuming that store-bought soil wouldn't have any diseases in it? Or is that not really the way it spreads?
Thanks again! (I am checking into the over-watering, too; we have had a lot of rain recently!)

[NicJean]

When growing indoors during winter, I'd suggest using sterile dirt (no eggs of nasty bugs, no mold, etc.) If you want/need "sterile" dirt - put a 2 inch layer in baking pans and bake at 400 degrees F for 30 minutes, turn oven off, let cool naturally (leave in oven with door closed, I let 'em sit overnight). Kills anything, but it does smell like dirt. I've only done this a few times, followed by a oven cleaning (which it needed anyway).
If your plant was outside - those spore thingies fly around in the air, nothing you can do about it, unfortunately.

[cheryl65]

Do you have drain holes in the bottom of container? Just a thought that maybe the water isnt draining thru and is just sitting there.