My lettuce:

Pepper

Yep, tomato looks too dry and possibly dead.

How are you watering? Do you leave the hose on at a trickle for an hour or two, to soak the whole bed a foot deep or so? You should only have to do that every few days at most. Weeks, once the plants are big.

Tomato and especially pepper look sunscalded. Did you harden them off before planting?

Lettuce looks fine.

NilaJones - I don't have soak hoses, just a regular hose. I was giving them a good watering (after lunch usually) every day. I stopped the past 2 days because I was thinking maybe I was watering to much? Is that possible when it's hot outside?

ltilton - I bought some of them from a Nursery that had them outside, and the others were from my "box" that I made with greenhouse plastic.. the lid was kept open during the day.

Should I replant or can I revive them? What did I do wrong so I know what to do differently next time? Should I hold off on fertilizing? How often to water on hot days?

What state are you in? All zone 8's are not created equal. I am going to say that overwatering is one of your problems. The tomato plant looks like "toast" to me and I would recommend starting over. The lettuce looks fine and the pepper should be on life support.

Here in Western Oregon Zone Eight we are having unseasonably warm and dry weather. But it is still too early to put out unprotected tomato plants. Those nights when it was "37ish" it might have been colder in your garden and the tomatoes don't like a chill and will react as in your photo.

(FYI: if you put your zone and location in your profile, it will appear on all your posts and give everyone a better chance to help)

Good catch, lonmower! I missed the 37 degrees comment and thought the OP was ina warmer location. That could very very well be frost damage.

OP, it doesn't matter if you have a soaker hose or regular hose. Turn a regular hose on to a trickle as wide as your finger, lay the hose down on the ground and walk away. After 30-60 minutes, move it to another spot, and walk away again.

The key is, do not stand there with the hose in your hand. Unless you are a srsbidnez meditation practitioner, you will water for too short a time.

lonmower - I put my zone (8a) on my message when I posted. You must've not paid attention to that section.

Thanks NilaJones for the help. I will start doing that.

Question about the lettuce.. It doesn't look fine to me.. maybe the picture isn't a good representation of what it looks like. It looks like something nibbled on it. Not all the pieces are the same and some are missing more than others. I am assuming it's a bug?? What should I do?

Herbicide drift? Did you or someone else in the area have a yard sprayed? With so many plants dying, it raises a red flag for me. Also, what are you fertilizing with? If it is a weed and feed fertilizer, then it could be killing your plants.

Just a couple of other ideas.

Jay

Things chew on lettuce. They're going to do that. But whatever it is, it's not greedy, it's leaving you most of the plant.

You can cover it with a row cover if it becomes a real problem. You can spray Bt if caterpillars get into it - identifiable from the frass they leave behind.

But lettuce leaves are the part you eat. Whatever you spray on them for the bugs, you're going to be eating it yourself.

You do realise that your lettuce is an oakleaf variety don't you? Just wondering. One leaf may have been nibbled but most are intact as far as I can see.

The pepper and tom both look like they could have got frost damage.