>>1599
>Irl all my gardening ends in desaster, barely able to grow small tomatoes or 5 inch pumpkins without them mysteriously turning brown and dying long before their time.
I remember you talked about salt mist from the nearby sea making rust bubbles on the cars in your area or was that another place? It does sound like salt, either from the soil or from the water. We'd need a pic of thee plants to make sure. Tomatoes are relatively salt tolerant though so that's a bit odd.
Or it's a fungus like Fusarium or Phytophthora. They can persist in the soil and reinfect new plants year after year.
https://gardenerspath.com/how-to/disease-and-pests/common-tomato-diseases/

You're a smart bear you should be able to figure out the root of the problem, I'd recommend starting with fresh compost next year to eliminate any sort of biotic or abiotic soil problems.