Clarification please... Do you mean the plants are rotting or the fruit.

Assuming this is a raised bed...
1) Did you put any type of weed barrier down before putting your soil in?
2) How much, volume and duration, are you watering? How often?

Are the tomato plants staked or supported in any way, or are the branches just lying on the ground?

Did you mulch around the plants?

Have you had any insect problems?

If possible, photos would be helpful.

Linda, what do you mean by purchasing a garden bed? Also, what do you mean by adding miracle grow to it? Your post is way to vague to know what you did to be of help. We all do want you to be successful so a little more information would help.

1. There is an Amish farm that made raised beds ( image attached- I hope)
2. I just tore up 1 of the zucchani plants because the zucchini was rotting
3. I did not put mulch in the bed.
4. Miracle grow is the name of a fertalizer we bought at our local garden place
5. I water the bed once a day for a few minutes ( all over)
Thanks for any help- never gardened before

Agree that much more information is needed including the size of this purchased bed that was filled with "topsoil".

Based on the info so far it sounds like there were several guaranteed failures built in from the beginning.

It is likely too late to save the existing plants but with some work a good fall garden may still be possible.

Dave

First that bed needs almost 3x the amount of soil it currently contains. Maybe 4x as much. They should be filled up to just a couple of inches below the top brim.

Second "topsoil" is never used in containers such as that. It compacts, doesn't drain at all well and drowns the roots plus it contains all sorts of potentially harmful elements depending on the quality. It needs to be filled with a soil-less potting mix - many brands available - plus lots of compost of some type. Compost and potting mix are both available in large bags from nurseries and even the big box stores. Determine the cubic feet of the box to determine how many bags you will need to buy and then, if you con't remove that topsoil, mix the new stuff in with it very, very well.

Third, read the directions on the Miracle Grow. It is supposed to be mixed in water and used to water plants, not mixed in with soil. Instead buy a bag of a good granular fertilizer - one that is not diluted with water - and mix the label recommended amounts in with all the potting mix. They will be rated with numbers such as 10-10-10 or 13-13-13 or similar.

Fourth, do not water daily. Water the bed well until water drains out the bottom (I assume it has holes for drainage, if not it sure should have), then plant the plants, then you water only as the plants need it, approximately every 3-4 days and you water deep, not briefly.

Hope this helps.

Dave

We do still need to know:

= Do you mean the plants are rotting or the fruit? Please give details or better yet, post a close-up photo which shows the rot.

= Did you put any type of weed barrier down before putting your soil in?

= Have you had any insect problems?

Also,

= What kind of Miracle Grow was it? There are several different kinds. How did you add it: dry mixed in the soil, mixed with water and used to wet the soil at the base of each plant, etc.?

= When you purchased the plants, were they in "peat pots," and did you plant the entire pot?

= When you stick your finger several inches down in the soil, how wet or dry is it??

Wow. Did I learn a lesson. I will be more prepared next year. I was off to such a good start as this bed comes with a cover so got an early Thanks for all your advise. Guess I will go to farmers market this year

looks like a nice planter (raised bed).
Digdirt is entirely correct on all counts except maybe the watering, that totally depends on what potting mix and type of plants and how big they are in the bed, how hot it is etc.

If it is good draining mix in a very good draining planter then you could easily water it every day.
I water mine about 6 days a week.

Buy some good "Potting Mix" not top soil, can amend it with some large perlite and pine bark to get it to drain better.

FILL that planter to within an inch of the top, make sure there are "several" drainage holes in the bottom.
On something that size with a flat bottom I would probably put 30 or more 1/2" holes in the bottom.

It is likely that if you just had that planter full of dirt, even heavy top soil that the plants may have at least not rotted. You have heavy soil, probably in a not so well draining container, with only that tiny amount of soil the roots are probably sitting in water in the "perched water" in bottom few inches of soil.

First 2nd and 3rd thing you gotta do is Drainage drainage drainage.