Your soil is dry. Tomatoes need even watering.

Are you growing this indoors?

I had them outdoors for most of their lives and brought them in when they had caterpillar infestations. So that's from the soil being too dry? I water them every other day.

I don't think its a watering issue. A couple questions.... How big is that container, how old is the plant, are you fertilizing, what zone are you in, etc...

The container is around 4-5 gallons. I germinated the seeds around May. They are around 5 or 6 months old. I'm not fertilizing. I have them in fox farms of soil. Maybe they used up all of the nutrients in the soil. Im not sure what you mean by zone? They are beinv grown indoors under 18/6 lighting. Does it look like a deficiency to you? Thanks.

11590 in your name says you're from Long Island? That's your zip code. The zone means the Horticultural zone which is 7 if that's where you're from. There are horticultural zone maps that give your zone based on the lowest temperatures during the year.

Plants in pots need fertilizer. Miracle Gro makes a tomato fertilizer that you use in your watering can. It's hard to grow tomatoes indoors unless you have a gro light very close to the whole plant, or direct sun by a window.

The USDA Zone numbers are actually based on the lowest temperature in the winter. They have nothing to do with the highest temps in the summer. As a result, the zone numbers are especially useful for perennials, and assessing freeze tolerance. While those numbers can give a general feel for summer gardening conditions, they are by no means accurate in that regard.

Yep, your soil looks bone dry. But I don't think that's your problem. Tomatoes will wilt significantly when they dry out. Yours aren't wilted. I have to suspect a fungal infection for the brown spots. But yes, container plants ALWAYS need added fertilizer. I'm surprised they grew that big without any. Garden soil has organics that, if outside, degrade and release some nutrients, but a container plant doesn't have the biological activity to do that degradation well. Tomatoes lacking nutrients just don't grow.

Fox farms soil has a lot of nutrients. But all of the nutrients are used up now. I'm going to get some fertilizer. U think it's a fungal infection? Can it spread to other plants? How can you treat it? Thanks for the help.

I'm in colorado

If a fungal infection, it's probably too late to treat it. Fungicides work to stop fungal infections from starting. To keep it from infecting other plants, just keep it away from the other plants, and dispose of the plants when they are done.

Potting soil often is amended with manure and or compost, but in a container, those won't break down effectively. Even then, the nutrient value is minimal.

I was thinking it might be sun scald. But I don't know.

Those plants look insanely good for being planted in may. Slight magnesium deficiency and some sort of burn or wind damage or something else mechanical. I have no idea how they still look ok without any added fertilizer. I think I added more than 200 grams of fertilizer per plant during the season (and it was needed).