Gardening Q&A: tomato blight

Horticultural advice from the experts at the RHS
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Question: I have just lost my tomatoes to blight - the fruit is going brown and mottled and the stems are going black. I have destroyed the plants but now have ten bucket-sized pots of infected soil and nowhere to put it. Can I spread it on existing soil if I don't grow potatoes or tomatoes? Any other suggestions? Also, what is the best way of disinfecting the pots?

Answer: It is sad to lose tomatoes but it is a very common problem when they are grown outdoors. In most cases, the infection occurs each year when the spores are blown in and the conditions are damp and warm. Spores can also overwinter on infected material, but they are much less likely to be in the soil. However, little is known about their survival in the soil and their potential as a source of disease, so some caution is wise.

Remove all infected material and put in green bin (the contents go to be hot composted, which will kill the spores). You can spread the pots of infected soil under shrubs and perennials or areas where tomatoes and potatoes are not going to be grown again. Washing the pots in hot, soapy water is good practice anyway, even though there aren't likely to be many resting spores present.

When wet weather is forecast from June onwards, protectant sprays are advisable, especially for outdoor tomatoes. Ferline, Fantasio and Legend are tomato varieties that are claimed to show some resistance but they, too, are likely to succumb in wet weather unless protected.

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