Q.Hi,could Someone Please Tell Me Why So Many Of My Tomatoes Have Gone Brown Even Though All My Other Plants Are OK And They Are All In
the same soil.thank you
Certified GKH Gardening Expert
That looks like Blossom End Rot of tomatoes that has also been attacked by a secondary fungus. This will be caused by a lack of calcium which can be from acidic soils as well.
I would check your soil nutrients and pH, and apply a fungicide, as well.
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-blossom-rot.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-guide.htm