Black bases on tomatoes

[Antaresisastar]

Does anyone know what causes this please? It's not on all of them and hasn't happened in previous years

Looks like blossom end rot. I think this is caused by not having enough calcium and the compost being too dry. More watering more frequently is required.

blight caused by a lack of water, you will have to throw them out unfortunately

It’s looks like blossom end rot, normally caused by inconsistent watering when the fruit is setting. The problem only begins to show when the tomato is about half the grown size. The good news is it doesn’t spread

They are in a grow bag but have been watered every day, at least once. Ihatethecold, do you mean the whole plant or can I just remove the black ones, such a shame. Thanks for your replies though.

Phoenix, that's better news, thank you.

Agree with others, it's a calcium deficiency. What are you growing them in, if in pots or growbags then irregular water-supply can cause this? The soil should never be allowed to dry out, which is why this is less likely if the plants are grown directly in the soil.

They are in a grow bag (3 plants, different varieties), I've grown them like this for the last 3 years but not had this problem before. I guess it's the extreme heat.

Have you been feeding them? As soon as the first flower pops they need feeding one a week with a tomato food or every day with a weaker seaweed solution.

and yes it will be the extreme heat, making it harder to extract nutrients.

I’ve got 12 tomato plants growing in same conditions on same site. Only the fancy Italian variety has blossom end rot. Other types are fine, so some varieties more susceptible than others

I have been feeding but admittedly perhaps not as regularly as I should, you just reminded me to go and do it! No fancy varieties, those in the photo are Shirley.
I guess I'll just pick the effected ones off as I see them and hope for the best.
Thanks for your help.

I've had BER on one of my plants this year too- marmande, the others are all fine. Just picked them off and put them in the bin. Feeding every other day now!

On the plus side, all this weather means my cucumber plant is fabulous this year!