Oops. I wanted to add that all of our yellow squash and zucchini died too. :(

Something similar happened the first year I planted my raised garden. I called my local agricultural extension office to find out what I did wrong. The horticulturist said that I have to let the soil "cure" for a few months. She said all the manure and organic matter I put in it is getting the garden soil superheated because it is breaking down so any plant I stick in it will not survive.
Look in the phonebook for your local extension office or find their website online. Sometimes a State of Florida horticulturist will even make house calls to determine your problem.
Hope this helps.

Dee

Another possible answer to your problem may be root-knot nematodes which are prevalent in FL sandy soils. Do a search to better understand what they are. When you pulled your dying plants did you happen to notice if the roots had 'bumps' all along the surface? This is a sign of nematodes. They are very difficult to control which is why many Floridians grow vegetables in large pots using commercially bagged potting soils.

Mind you, I don't garden in Florida (east central Mississippi), but if I were betting, here are some things I bet went wrong:
My first bet is your watering schedule. Unless your soil is pure sand (Not, since you amended it.), your plants do not need to be watered every other day, and certainly not for 25 minutes at a time! You also mulched, which will help the soil retain moisture longer. In my area, an inch of water per WEEK is considered ideal. I know it's hotter there (Our high temps average in the low to mid nineties through the hottest part of the summer), but still, that sounds like way too much water to me. If you're in doubt, check with your local Agricultural Extension Service. They have pamphlets and such that will be helpful to you.

2. You don't say when you planted your garden. Typically, you want to plant once your nightly low temps are above 50 to 55 degrees. Here, that is in early to mid April, probably even earlier for you. In our area, most folks have harvested the majority of their garden by mid July. Once the hottest weather sets in, alot of plants (tomatoes, especially) will stop setting fruit. Depending on when you planted, this might be the trouble.

3. Miracle Grow (nor any other commercial fertilizer) should never be applied to plants that are already stressed and not thriving. Once a week is too often. Label directions say to apply Miracle Gro every two weeks, and honestly, that's still alot of fertilizer. If you add compost, manure, etc. to your soil each year before planting, you shouldn't need nearly that much fertilizer. The only way to know for sure is to have a soil test. And here's another possibility.

4. Why did you add lime? If you had a soil test and the test indicated that lime is needed that's one thing. But if you just added it, you may have done yourself in right there. Most vegetables like a neutral to slightly acid soil PH. If you over did it (or under did it) that could definitely explain your problems.

Do not despair! Contrary to popular belief, there is no such thing as a "born gardener". Knowledge is the key, and it's widely available. Read all winter. Look for and attend gardening classes and seminars. Ask questions. Get your soil tested. Visit your Ag Extension office. Take a Master Gardener Class. (You're a Master AFTER, not before you take it.) Try again!! And be grateful that your family won't go hungry while you're learning. :)

gardening , you posted : I don't know WHY my plants died !

Wrong plants
wrong place
wrong time

You are a newbie to Florida gardening . Give yourself a million breaks . Gardening here is not easy all the time and not like any where else .

Step 1. ) go to the Florida forum on Garden Web and read , read , read . Use the search and read the archives . Ask questions there .

Step 2. ) After reading and studying - go to your library and check out books on Florida gardening . Other general books will not help . There is no other place like Florida for unique gardening challenges .

Step 3 . ) Use the solutionsforyourlife.com website . It is full of Florida gardening advice from the University of Florida . There you can find a link to your local Agricultural Center .

Be kind to yourself . Read , study and go slowly . You tried and deserve tons of kudos for that.
donnabaskets was right with all her advice. Florida weather is very similar to Ms - mid 90's in the summer and humid ! Even now the night time temps in central Florida are still in the 70's .

Just wanted to thank you all for your advice. We have recently replanted and are having a bit better luck this time around. We actually have green plants instead of brown plants. I'm determined not to give up and will just do my best to learn about the process!!