Probably you have :

=== sandy soil

=== Nematodes

Probably

Please check with your local ag center. Certain tomatoes grow better in Florida. We grew heirlooms a few years ago and we are a zone above you. They didn't fare well.

thank you all for the comments... last year i planted a few plants got blight and everything else except a good crop... my soil is pure sand 6" down so I dig a hole and put good potting mix in it..still didn't do well. probably every disease known to maters....I also bought some good heirloom seeds and planted them in an EarthBox in the fall... they were doing great for a while...then got worms, fungus and other stuff finally the blight took them out..... tried container growing failed....

My veg gardening experience was up north (zones 5b & 4b )and I always had a great great crop. fed the neighborhood.....Notthe same where i live now in 9b. I'll check out the Florida gardening forum thanks.... just need to find the right varieties for this area.

That was my point - it isn't the variety that is the problem, it is the very different conditions provided. No variety will do well in a hole dug in sand and filled with potting mix. No variety will do well in areas of high humidity without the use of a fungicide regularly. No variety, be it hybrid or heirloom, will do well if planted at the times used by northern gardeners but can thrive if planted at the proper time for mid-Florida. No variety is blight or any other fungus resistant, no variety is "worm" resistant, etc.

So focusing on variety won't solve the problems, Creating better growing conditions and recognizing the different needs of plants growing in your current environment will. For example, you can make an 18-24" deep raised bed on top of the sand and fill it with a good mix of soil and compost and nutrient supplements. Plant your plants out in early February to beat the heat and again in mid-Sept. after the worst of the heat breaks (not in April or May) and plan to shade the plants as needed. Plan a regular weekly schedule of fungicide spraying from the day of plant out just as all of us do who live with high humidity do. And patrol for pests ( horn worms and/or fruit worms, etc.) daily and deal with them as needed before they get established. Prune as needed and increase plant spacing to increase air circulation in and around the plants. Water and feed far more often than you did up north.

Gardening in Florida sometimes takes more work and more attention according to experienced Florida growers. And very different timing than in other parts of the country but we all have different conditional needs no matter where we live. But the variety planted is not the issue.

Dave

Yeah, I took a wild guess on sandy soil too.

As Dave suggested probably building a raised bed is your best option, Otherwise amending soil with so much sand there might not give you good results.

Raised beds come handy both where you have heavy clay soil OR sandy soil. Clay soil compromises drainage and sandy soil compromises moisture retention.

This is a link with a planting guide for FL that might be useful, beside that planting in container seems to be the best option in my experience to avoid nematodes and watching for hornworms on a daily basis is the only way to go.
UF Vegetable Growing Guide for Florida

Thank you all for the great input... wow, I've been doing everything wrong.

maybe you all could tell me the specific sprays I should have for each diease. I have some but probably not the right ones. If I can get the raised bed in soon, what soil/nutrients schould i mix up? What type of wood would I use to build... it? if this is too much info to send, I'll understand.....thank you all very much

Bruce

Bruce anything for a raised bed will work. I worked in a East Texas a few years ago and it very much reminded me of Florida. I built raised beds for a friend of mine in Hudson, Florida a few years ago as well. We hit all the box stores, and nurseries for any busted bags of compost, cow manure, top soil, raised bed mix, and so on. The busted bags were cheaper, and they went into the back of a pick up truck so being messy was not a problem. If you can get it I would put in a lot of landscaper's mix. Sometimes labeled as soil conditioner. It is composted pine bark fines with some trace of manure, and sand. For his raised beds we also mixed in a bunch of vermiculture. He has been doing great with tomatoes, peppers, and melons so far.

For fungicide I like Daconil. It works well for me. I tried copper Bonide. It did not work near as well as Daconil. I use what works for me. For the worms I spray with BT as directed. I also keep my eyes open, and check things every day for pest.

My biggest pest is not one that harms the plants themselves. It is fire ants. I have to control them so I can work in the garden without having myself covered in ant bites.

I appreciate your help a lot