Tim wrote"This was Bayer's reply The leaves look like they are suffering nutrient deficiencies.
they distinctly yellow leaves would perhaps indicate nitrogen deficiency and the purple leaves with the yellow vein areas of the leaf would indicate a manganese deficiency with often the older or more mature leaves being affected. "
The "more mature leaves being affected casts a bit of light on it Tim" ..What we have found is that stuff germinated OK, potted on OK Didn't show any signs if anything being amiss till plants were growing on . Then a bottom leaf or 2 looked sort of not right etc eventually the whole plant looked sick with the symptoms as you describe ..
Despite all that we have tried from seeing the first signs as in foliar feeding etc it ain't cured it .We have found the plant wont take them in ..
The affected plants have remained near useless, looking a right sorry mess and quite a lot have keeled over entirely ...
This has happened to a few of us but not to others on the site so we looked round for a common factor. What we have come up with so far is this.
All of us that have suffered in different degrees seem to have used the same general purpose compost this year ..It was new one to us, the allotment society bought a load in and it was also being sold locally by a few garden centres etc ..
There's four of us with adjoining lotties that sort of grow plants for each of us as I will grow one variety of say asters or broccoli and others will grow differing ones which we all share about .Three of us have used this medium this year .The old guy that didn't but stuck to his usual stuff ..Upshot is ours have been affected his hasn't so far ..We have hanging baskets quite a lot of bedding plants all in trays and potted on ready for going out which we keep looking at with perhaps a paranoid eye now ..
The maddening thing is it don't seem to show till plants are well on their way and it seems by then it's too late..
As a footnote to it being adverse wether conditions it has affected cucumbers and toms etc which have been grown in a heated greenhouse ..
It ain't all doom and gloom some stuff seems to be OK ..
I hope this post keeps running as it will be good to see the outcome of all this ..