What/where are they planted in? Borders/pots/grow-bags? What brand of compost are the seedlings in? Is it the same brand as the big plants?
Having seen the effect of a certain type of compost on some tomato plants last year, compared with plants from the same batch in different compost, I wouldn't rule out the compost itself being a problem.
Having seen the effect of a certain type of compost on some tomato plants last year, compared with plants from the same batch in different compost, I wouldn't rule out the compost itself being a problem.
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