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Calcium or sulfur defiency in tomatoes.

I am growing San marzano tomatoes in a plot for the first time that had courgettes last year but I renewed the soil with leaf mould and general fertiliser in winter.

They are outside.
Also should I stake then/pinch them as it is my first time growing this variety.
Thanks very much

The top leaves are going yellow which implies a nutrient deficiencies. Please can someone confirm which one


  • NollieNollie Posts: 7,032
    Unlikely to be calcium deficiency unless you have very acidic soil, do you? Looks more like magnesium deficiency to me, where the leaves in between the veins go yellow. I have never seen sulphur deficiency so don’t know what that looks like...

    Maybe do a soil PH test of that particular area? Get your sample from real soil, well below the leaf mould, which may throw the reading.

    No, don’t pinch them out, at least not the tops, they will want to get a whole lot taller, and need sturdy support, before you do that, but do pinch out the side shoots that appear between the main stems and the leaf axils.
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • Jason-3Jason-3 Posts: 383
    Whereabouts are you in country Daniel? Unless you are in the warmer parts that yellowing may be as a result of cold nights as opposed to a deficiency.
     Most of the UK has had quite a few nights hovering around 5 degrees the last few weeks which is on the cold side for plumb tomatoes
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