You should probably have your soil tested by a professional lab. That would tell you very specifically what is present in adequate supply and what is deficient and the best ways to address that deficiency. Adding organic matter is a good first step but it will not necessarily address all your nutrient issues.

It may also be worth investigating the type of tomatoes you are growing, the seed source and when they are started or set out in the garden. This too can have an effect on productivity.

And FWIW, questions such as this specific to soils, soil fertility and nutrients would be better addressed in the Soils, Compost and Mulch forum.

This forum is not all that active and really wasn't established to address these sorts of issues.

Thanks we don't have professional gardeners here unfortunately but next time I'll post there.

"we don't have professional gardeners here"

Billy, I'm not sure of the relevance of this statement but it does bring up an important point and that is your location - where you live makes a huge difference on how you approach gardening and what kind of advice will be meaningful to you. I'd suggest you edit your profile/screen name to include your USDA hardiness zone or at the very least, a rough geographical location. See mine as an example.

If you need help in finding a soil lab in your area or preparing a soil sample for testing, just let us know :-)