cabbage leaves turning yellow with black spots

[bobt]

Hello everyone,

I have some cabage growing in square container the stalks are now about
6 weeks old and just this past week iv spotted some of the leaves have
turned a yellow colour and have black spots on them.

I give a regular once a week feed with water and every 2nd week
some water with seaweed mixture .

I know its not a good sign, yellow leaves with black spots,
can anyone offer advice, i can email pictures.
if people want i dont know how to show in the thread a picture .

any advice is appreciated.

cheers
bob

[heskie]

Originally Posted by bobt

Hello everyone,

I have some cabage growing in square container the stalks are now about
6 weeks old and just this past week iv spotted some of the leaves have
turned a yellow colour and have black spots on them.

I give a regular once a week feed with water and every 2nd week
some water with seaweed mixture .

I know its not a good sign, yellow leaves with black spots,
can anyone offer advice, i can email pictures.
if people want i dont know how to show in the thread a picture .

any advice is appreciated.

cheers
bob

Hi Bob,

I have had leaves go yellow, usually the older leaves and occasional spots, but not enough to ruin a crop. Have a look at this it may be helpful:

Which advice

Have a look here also at advice from the RHS

[timbrenn]

Bob emailed this photo to help diagnose the problem:-

Hello, im enclosing a photo of the leaves that have turned yellow with black spots.
i know its an effection and its now spread to many of the leaves.

I went to the local nursery but there was not one person who knew about it.
i believe they are only saleswomen and not hortaculturalist, for me if they dont
know about pests and dieseses they shouldn't be allowed to work in nurseries.

[DaveB]

From what I can see in the photo most of the leaves visible are the first seed leaves, the yellow one has just fullfilled its purpose and is decaying as will all the other seed leaves as they are replaced by healthy true leaves. the black spots are probably fungal growths attacking the decaying leaf.
There appears to be a very large amount of plants in a small space, at six weeks they must need transplanting or thinning to produce healthy plants, even the smallest of cabbages need a space of at least 6ins by 6ins to mature properly and I would prefer more space than that. I am afraid one of the problems with container growing is the temptation to have too many plants and the crop is deprived of the air and space needed for healthy developement.
Hope this helps.
Dave.