In sandy soil (as I've got as well) nutrients can leach out into the ground when it rains and when you water. So keep adding more of what you're already putting in. Those organic amendments will increase the health, nutrient and water retention of the soil. As far as "washing away", the best way to prevent that is with a good layer (at least 3") of mulch. (Shredded leaves, grass clippings, newspapers - no glossies; weed free straw or hay.) Not only will that supress weeds, but more importantly, hold in the amended soil and cut down on watering needs.

Remember to keep the nitrogen low. That will only promote leafy growth at the expense of fruiting. Add more calcium in the form of bonemeal or crushed eggshells (although these take at least a season to break down and offer up enough calcium) and some kelp/seaweed.

The last thing I 'd suggest (and actually the first thing you should really do) is to contact the agricultural extension agency in your city/town or check the yellow pages for some vegetable (especially tomato) growers in the area and ask either or both how to get more fruit from your tomato plants. Most folks in these fields are more than glad to share their success stories or offer up information.

Good luck. :)

Gardenz? From OG? I'm happy to see you here!

(Sorry for not responding to your question Lynn. I don't have any advice to offer.)

I heard other Fla gardeners complain more about nematodes in the soil ruining tomatoes rather than nutrient loss. Not a problem here in Va so can't help much, sorry.

I've had great successes & terrible failures w/ tomatoes in the ground here near Tampa Bay.I grow from seed organically w/ no synthetics.

Variety is crucial - some have NO resistance/tolerance to the common problems here.Lotsa compost, straw/hay mulch, foliar feeds (Maxicrop, compost tea) & indeterminate varieties all help to ensure success for me.

& don't rely on local stores to offer appropriate varieties either - I've seen plenty of common Northern varieties @ the box stores that just won't grow here.

I always try to grow indeterminates - which can often out grow many problems.Some OPs that have done well for me (in no particular order) are:

Great White
Matt's Wild cherry
Hillbilly
Black Plum
Polish Linguisa
Grandma Mary

For hybrids - the more letters after the name, the better:

Veronica
Viva Italia
Big Beef
Sungold
Sweet Chelsea
Lemon Boy

UF IFAS/EDIS has some good articles on veggie gardening basics here in FL - w/ recommendations for varieties.& definitely contact your county extension - ours here in Pinellas is terrific.

Below is a good site for reference on varieties, as well as purchasing - they're in Ft. Myers....

HTH

Here is a link that might be useful: Tomato Growers Supply Co.