Hi my tomatoes are going black underneath any body know what the problem is,and the solution, don't want to lose what until now appears to be the best crop to date.
Is this on the actual tomato ? Blossom end rot, if it is. Irregular watering and letting the soil dry out causes a loss of calcium which the plant needs. Never been able to save a plant once this happens. But, if you want to try - regular watering, feeding and moist compost is key.
Sounds like blossom end rot Jazzy. Usually happens when watering's a bit haphazard -ie if the plants dry out too much between watering- it prevents the fruits taking up nutrients properly.Keeping the soil moist usually prevents it - difficult with the weather this year too. When you feed, make sure the soil is moist first otherwise it runs straight through (I'm assuming you use a liquid feed) Nothing you can do about the affected ones unfortunately.
if you catch them before too much has gone black you can make chutney out of the good bits.
It does sound like BER. Here it is in an advanced state:
It's not just irregular watering that can cause it though it can be a factor. Keeping the soil moist isn't a factor. BER is caused by plant stress stifling the plant's ability to distribute calcium to the fruit via its internal mechanisms. Strong winds can cause it, seriously fluctuating temps, overfertilising, etc. Anything that will physically stress the plant.
In addition, some varieties - the plum-shaped ones, like San Marzano, etc - are simply genetically prone to BER. No one knows why.
One or more tomatoes on a plant suffering BER doesn't necessarily mean the plant's entire production will suffer. If whatever is causing the plant stress is addressed, later toms will be fine.