One of my friends has given me various tomato plants as swops. Both the ones he gave me and many of his own are developing yellow leaves. Naturally our first suspicion was magnesium deficiency, but his gardening encyclopaedia says that the veins stay green or go yellow too. Ours have yellow leaves with purple veins which suggest something else, but what? I can only think it's some sort of virus as they are in different composts and some even in borders. Any ideas?
Too much water maybe ?? One of my sunflowers also has yellow leaves and I am not sure what it is. I thought it was overwatering but hope someone can give us advice !? ??? ::)
Hi DJ. Well, it doesn't sound like blight and it's a bit early for that so I think it's either as you suspect or over-watering or the cold. I'd give them a dose of foliar Epsom Salts anyway, make sure they're not too wet and ensure they are warm enough over night.
G xx
Tomatoes are susceptible to fluctuating temperatures prevalent at this time of year, particularly, cold nights could stress the plants. They should buck up as temperatures get more stable. Hope so anyway!