You're using a soaker hose?

If so,how long each irrigation?

If not, what system are you using?

How do you determine you have add adequate water?

And how do you determine when to water again?

i irrigate for about 30 min every other day when it is hot out. before i water i will dig down into the soil a little bit to see how moist the soil may be. It is usually pretty dry. I am using a soaker hose at the moment. is that not a good method?

Is this a new bed meaning newly created with new soil in it? Or is it a revamped bed in which you've grown tomatoes before? Did you grow your plants from seed or buy them? If bought, did they all come from the same nursery?

Those are classic signs of soilborne wilt, but it would be unusual in a new bed, and it would be unusual whether in a new or old bed for all your plants to get it at once.

Do you live in a location with a cooperative extension program?

gorbelley,

It is mostly new soil (consisting of peat moss, vermiculite, and organic compost manure) however did reuse what I had previously been using in a 4x8 bed that I grew tomatoes in for the past 2 years. I started the plants from seed.

Could it be a grub problem? When I transferred the soil form the old bed to the new I noticed some white grubs which means there were more that I probably didnt see and are now within my new beds as well.

I have not heard of a cooperative extension program so will have to look into it.

Where are you located? In the USA? If so, what state?

south western part of ohio

It looks like fusarium to me. But you'll need to get confirmation since, as previously noted, a lot of things, especially watering and nutrient issues, can cause similar looking symptoms. If you have a plant that you're basically done with, you can pull it and slice the main stem lengthwise to look for the telltale brown vascular tissue.

The cooperative extension in your state is through OSU. You can locate your county extension office here. Sometimes county extensions have disease clinics where you can bring in samples for diagnosis or other resources. For example, in PA, my local extension office has disease clinic hours twice a week during which I can bring in a diseased plant, photos, and/or samples and have an expert help me with a diagnosis.

How deep, and wide, does the moisture go after you irrigate?

I'll stick to water stress.

My beds are fairly saturated. They are 6" deep. I always check before watering to make sure the soil isn't wet. Is sometimes a little moist but mostly it is pretty dry before watering

I think Jean's point is that they might be too dry.