Garden foe - tomato blight

2020 hasn’t been a great year for growing tomatoes, with lack of sunshine and warmth holding them back. Then in many gardens, and even in some greenhouses, tomato blight struck.

Phytophthora infestans is a fungal disease which wreaks its havoc quickly. Spread by the spores on the wind and loving warm, wet conditions, it can devastate all parts of the plant within a week, ruining the crop. Plants grown in a greenhouse are more likely to be safe from attack but there are some general principles to apply to all tomatoes whether grown outside or under glass:

  • Keep the plants dry by watering the roots, not the leaves. If the weather is wet, try to provide some cover from the rain

  • Keep the plants well ventilated and well-spaced so air can circulate. Also, remove some of the lower leaves to increase air flow and reduce humidity.

  • Feed with a specialist tomato feed high in potassium, not one high in nitrogen which will increase leaf growth making the plant more prone to blight.

  • Avoid growing tomatoes near to potatoes which are also susceptible to the same blight.

  • Keep diseased plants out of your compost bin to avoid a re-infection next year. That is the advice from Gardeners’ World, however Charles Dowding, the no dig guru, says this is not necessary as blight is an airbourne disease, the spores are not carried in the soil.

If all else fails, there are some tomato varieties that are more resistant to blight. You could try these: Berry, Fandango, Fantasio. Ferline, Latah, Legend, Lizzano, Losetto, Red Alert.

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