[duckling]

Dear All

I have a bit of a problem with my otherwise beautiful San Marzano Tomatos.  They seem to be rotting from the bottom up.  I have not grown this type before and so it is really baffelling me.  I would say well over half of my crop is or has gone this way.  Please see the pic attached.

It is so demoralising when this happens, both my husband and I have worked really hard on keeping our tomatos watered regularly, supported as they have grown and fed every weekend.

Looking forward to hearing your advice people.
Thank you.
Regards
Duckling.

[oldcow]

It looks like blossom end rot. The root cause is a lack of calcium. Sometimes it could be that the soil is lacking calcium, but most of the time it's due to insufficient or irregular watering, since the tomato plant cannot get the calcium out of the soil if it's not watered enough.
Nothing you can do for the tomatoes that are already affected, but if the problem is watering you should be able to correct the problem and save the remaining tomatoes.

[mumofstig]

and for whatever reason, San Marzano seem to suffer from it when other tomatoes have the same amount of water and do fine
So IMO you may be better off with a different variety next year.

[paintedlady]

and for whatever reason, San Marzano seem to suffer from it when other tomatoes have the same amount of water and do fine

oh, I've got a good excuse now    Last year I grew San Marzano in the greenhouse and got LOADS of fruit but was upset about the number that had blossom end rot ... though I'll hold my hand up and confess that the watering was perhaps not so regular as it should have been, especially when it was raining outside   ...

[duckling]

Thank you for your responses.  I think I will try something else next year.  Probably more Moneymaker to make more Green Tom Chutney (Val's recipie of course!).  Its nice to know its not just us.

[Rowan]

Just to put your mind at ease, all our San Marzano have blossom end rot, despite our cherry, beefsteak and tigerellas being brilliant this year...

You can still eat the part that has not rotted it doesn't affect the taste. I'm going to grow something else next year...

[gillie]

I have been growing San Marzano Redorta (from Franchi).  It seems to be much less prone to blossom end rot than the plain San Marzano.

Gillie

[mumofstig]

I have been growing San Marzano Redorta (from Franchi).  It seems to be much less prone to blossom end rot than the plain San Marzano.

Gillie

Gillie and I beg to differ on this point

[barbarella]

I think the bigger tomato varieties generally seem more prone to blossom end rot.  It has been particularly bad on my Cuor de Bue tomatoes this year while the Gardener's Delight and cherry tomatoes have been unaffected. 

Having said that, the crops have been particularly good and early ripening this year with no sign of the dreaded blight (fingers crossed!)

Like Rowan, I just cut off the black bit - it doesn't matter at all when you are cooking with them.