[Bernard]

I grew Gardeners' Delight for years in a small greenhouse with no problems then a few yrs ago started to get this problem, in grow-bags, of lower leaves yellowing with purplish veins. Later leaves are more sparse than normal, though a crop of fruit does occur.

Last yr, planted direct in soil & had superb plants.

This yr, planted direct again but back to the old problem. It looks like this:


Can anyone please identify the problem?

[mkhenry]

There must be something good on TV for you not to have had a reply yet.So in the absence of the members who really know I am going to say it looks a little like Magnesium Deficiency.Serious and common.Use a multitonic on the compost to bring the magnesium levels back up.

[Aunt Sally]

I think you're spot on Henry.  Intervein chlorosis is caused by Mg deficiency.

[Bernard]

Thanks for the reply, folks.
I thought it might be Mg deficiency. What I don't understand about that is these plants have not yet reached the stage where feeding is advised. In fact, I have 6 plants in pots which are still only 6" high, sown much later than the others as an insurance measure against possible frost losses, and these are also showing the signs.
So it appears that early feeding with Mg is necessary. Any comments on this?

[dawninspain]

Hi Bernard - the general feeding of tomato plants should not start until fruit  has set and then you need a high potash fertilizer. Your magnesium shortage is a separate problem. Epsom salts I think might help.

Try this link for more info:
http://www.rhs.org.uk/advice/profiles0706/tomatoproblems.asp

Dawn

[Bernard]

Thanks for the link. I have sprayed with mag sulph so I hope the plants will improve. It seems, however that this problem is bound to occur if plants are grown from seed in general purpose compost. I shall introduce a small quantity of mag sulph in future.

[Salkeela]

Thanks for the link. I have sprayed with mag sulph so I hope the plants will improve. It seems, however that this problem is bound to occur if plants are grown from seed in general purpose compost. I shall introduce a small quantity of mag sulph in future.

Ah this makes sense.  I grew loads of seedlings this year and some that stayed in their pots a bit long turned yellowish only to recover when put in soil.